WELCOME to the anvilfire Guru's Den - V. 3.0

THIS is a forum for questions and answers about blacksmithing and general metalworking. Ask the Guru any reasonable question and he or one of his helpers will answer your question, find someone that can, OR research the question for you.

This is an archive of posts from June 9 - 16, 2002 on the Guru's Den
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Can You Give Me A List Of Stampes Used By Jewlers On Precious Metals?
   rexx - Saturday, 06/08/02 23:11:12 GMT

Dude what safety equpiment would be best for the Grinding wheel???
   arcomadose - Sunday, 06/09/02 02:10:25 GMT

I am a student researching civil war manufacturers of lead and was hoping you might know what the stamped initials M.A.H. on the back of a lead pig circa 1860s stood for. Thanks for your time.

   Lillian Azevedo - Sunday, 06/09/02 02:46:26 GMT

Benchgrinders are a dangerous tool if improperly used or if used w/out the proper safety equipment. Look at iFORGE demo number 66. It shows a nasty accident that happened to a smith here on anvilfire. When I am at the grinder or using an angle grinder I wear close fitting (not loose or dangling) clothing with full sleeves, boots, gloves, safety glasses and a face shield. Proper protection can save you losing a slab of flesh, an eye, or teeth. Bear in mind that if a bench grinder grabs the work out of your hands it will fly at a speed proportionate to the speed of the wheel. And if using an agle grinder and it catches and bucks, the same is true but it will be the grinder that flys. Be careful!
   Rooster - Sunday, 06/09/02 04:53:00 GMT

Rexx - Your question is not really specific enough to answer in more than a general way. Do you mean hallmark or touchmark stamps, or do you mean embossing and chasing stamps?

There are literally thousands of embossing and chasing stamps (properly called punches)used by silver- and gold smiths world wide. Dozens of standard patterns are sold by suppliers and most smiths make many or all of their punches as they need them.

Maker's stamps, alloy stamps, karat stamps, guildhall and assay hall stamps are just as varied. For an overview of a few of the most common grade stamps, guildhall stamps, and assay stamps, you can check in Metal Techniques for Craftsmen by Oppi Untracht. Goldsmith's Hall in London, Englalnd is the repository for most of the historical stamps.
   vicopper - Sunday, 06/09/02 05:28:53 GMT

What didn't get metioned here is that the dust and grit that the grinder throws up ends up in your lungs and a lot of it stays there and gets surrounded by scar tissue so you loose lung function. It is a serious matter and cumulative, so , wear a good quality dust mask and change the filters often...you'll be suprised at how fast they load up. Save the gasping for something more enjoyable.
   - Pete F - Sunday, 06/09/02 05:42:40 GMT


What kind of grinder? There are dozens and each has its hazzards and necessary precautions. Bench grinders, surface grinders, cylindrical grinders, tool post grinders, angle grinders, die grinders, head grinders, chop saws, tool grinders, belt grinders, coffee grinders, pepper grinders :) . . . .

Safety starts with proper testing and instalation of the wheel. Guards must be in place AND properly adjusted. Many grinders have been manufactured in the last 50 years that did not have proper guards even though they were standard on most industrial devices they were often left off of "consummer" devices or were options. See our second iForge demo on safety.

Vitrious wheels such as used on bench grinders and many others must be ring tested before installation, they must have the paper washers in place (they often fall off old or cheap wheels), they must fit the arbor and have proper fitting flanges or drive washers. After installation it is recommended to run them for a test period of up to 10 minutes with nothing and nobody inline with the wheel. After testing the wheels must be trued using a wheel dresser, PREFERABLY a diamond type. In use the wheels should be inspected occasionaly and dressed to keep round and running true and vibration free.

Almost all books on machine shop practice cover the details of the above as well as wheel selection and application.

Then there is personal safety equipment. . . This also varies with the type of grinder as well as the material being ground. In most applications safety glasses are a minimum assuming you already dress properly for shop work (long hair tied back or covered, no loose clothing, ties or jewelery, cotton clothing, proper footwear).

Leather shop aprons are a form of armor and prevent things like wire brushes and grinding wheel from grabbing your shirt or pants and pulling you in OR the grinder into you. Many applications require face shields AND safety glasses.

Flexible wheels and semi-flexible wheels such as used in angle grinders have fiberglass reinforcing and fill the the air with short broken glass fibers. Long after the swarf has fallen to the ground these are THICK in your shop air. I recommend good forced shop ventilation. This protects you from smoke, dust and fumes. The smaller your shop space the more important the need for good ventilation.

Grinder safety starts with machine shop courses or text books for the same, continues with the manufacturer's instructions and ends with common sense and attention to you, your equipment and your surroundings.
   - guru - Sunday, 06/09/02 06:50:23 GMT

Rexx, as vicopper noted your question is too broad and ask the impossible. Stamps used on any metal in general start with the letters and numbers including letters in dozens of languages (such as Arabic, Hebrew, Chinese, Cyrillic). That gives you three or four hundred without including the thousands of Chinese characters. Then look at the standard typographic symbols and geometric shapes.

If you go to our touchmark registry there is a link to a hallmarks site.
   - guru - Sunday, 06/09/02 06:59:45 GMT

Nicholas, A Sword? Dang, son, you got plenty of ambition! I have never made a sword but the metallurgy would be about the same. Except for the length to thickness ratio that would present a formidable challenge in keeping it straight. I would recommend tempering it to a low hardness just to minimize the chance of breakage. In fact, if it is to be a display item, why bother to heat treat it at all? Legend has it that swords were quenched by heating them to blood red and plunging them length-wise into a slave. I will leave it to you to fill in the details, however, the salty blood must have behaved much like a slow oil, only with a lot more screaming and yelling. Probably tough to get volunteers for this today. By the way, if you want to get an idea of what blade making is all about, find yourself a railroad spike and follow the tutorial on this website. Going from spike to blade is a lot like work.
   - Bob Nichols - Sunday, 06/09/02 15:38:14 GMT

Ok, now I have a question for Guru. I am a hobbysmith with a WhisperBaby and a 60Lb farriers anvil. Good for light stuff but I'm set up in my garage and can't really see me getting so good I can beat out a plowshare, anyway. I have made 6 very serviceable tongs (thanks to the tutorials here) but do not have any sets, fullers or hardies. New ones must be gold plated. Is there a source of used tools or is there a way a hobbysmith can make these items when it usually requires the use of these items to make them?
   - Bob Nichols - Sunday, 06/09/02 15:43:16 GMT

rexx-- you mean the karat stamp required by law? any comprehensive jewelrymaking text book lists them. Check the library.
   miles undercut - Sunday, 06/09/02 16:51:51 GMT

My son is doing a research paper on blacksmithing during the renaissance. He needs to find out what daily life was like. Can you give a web site to find this info?
   Branden - Sunday, 06/09/02 17:34:45 GMT

Hardys Bob, These are usuraly best bought. However, it IS possible to arc weld a shank to the side of a piece of tool or spring steel that is wider than the hardy hole and then sharpen it. It won't be pretty but it will work.

See iForge demos #41, #45, #49, #57, #88 and #133.

Demo #88 shows fullers with wrapped handles. This was a common technique for thousands of years and is still used today. It is much easier than punching handle holes and works well on many types of tools. It is only since the machine manufacture of tools that handle eyes have become universal in most handled tools.
   - guru - Sunday, 06/09/02 18:48:12 GMT

Well, CA CS, It was a real pleasure having the poster boy for Anti-Social Behavior visit the site! Whenever you get a chance to come back, DON'T!
   - Bob Nichols - Sunday, 06/09/02 19:13:40 GMT

Guru, I went through the iForge demos after I posted my question on making hardies, sets, etc. . The problem is I don't have an arc welder. Looks as if that ought to be my next purchase! In light of some of the sociopaths that have stumbled onto this GREAT site, I am going to use my Pub member name from now on. Just call me Quenchcrack.
   - Quench Crack - Sunday, 06/09/02 19:19:01 GMT


Life for a blacksmith would not have been particularly different than for any other person of their social class during the same time (the matter of social class being different from place to place, smiths being in high esteem in some countries and low in others). The Master smith would have been either a tradsman or a small merchant. His workers would have been been Journeymen and apprentices. Daily life in the blacksmith shop changed little from the beginning of the iron age until modern times.

Outside the shop the basics of life did not change much until the 20th century. There was no refrigeration so food was either fresh from the source TODAY or spoiled unless preserved by drying, salting or pickling. There was no running water and people bathed much less often than today. There were no toilets or sewers so chamber pots were common in cites as well as open drainage ditches. Rats, flies and desease were common. You could die or lose a limb from a minor scratch or burn. It was common to work at your job 10 to 12 hours a day. Life was close to the earth.

Years ago I was asked a similar question and wrote the following. The story takes place in 18th century colonial America but it could have been anywhere, anytime from about 1000 AD or earlier until the the end of the institutions of bonded servitude and slavery in the mid 1800's.

A Day in the Life of a Blacksmith's Apprentice

You can find other stories, myths and legends about blacksmiths on our Story Page.
   - guru - Sunday, 06/09/02 19:20:05 GMT

I just ignore people like that.
   Rooster - Sunday, 06/09/02 21:50:56 GMT

My Oppologies for not seeing and removing the note from the anti-social low life sooner. IF you see anything of this type on the site please drop me a note and I will attend to it. I have tracked down his ISP as follows and will track down his name soon:

La Cite Collegiale (NET-LACITE)
801 Aviation Parkway
Ottawa, ON M6K 3G9

   - guru - Monday, 06/10/02 00:12:29 GMT

I must have missed something. CA CS?
   Paw Paw Wilson - Monday, 06/10/02 00:14:34 GMT

Is spring steel usable for the making of tools (chisels, punches, fullers etc) or is it better to use tool steel? Also does anyone know of anything that would be likely to be found in a junkyard that is tool steel.
   888 - Monday, 06/10/02 01:09:11 GMT

I have a hammer question. It looks exactly like a cold cut hammer with the exception of its size. At just under 11" and close to six pounds with no handle. The eye hole is 1-1/4" X 13/16". Would this be just a very large cold cutter or something else?
   Chris - Monday, 06/10/02 01:49:11 GMT

Tim is now known as Rooster.
Funny you should say that. I saw your post after his so I thought you had seen it but decided not to remove it. I usually ignore malcontents like that but I think of the younger folks that frequent this site that don't need to be exposed to that sort of trash. Glad you removed the post. I hope you get a name!
Join CSI! The view is cooler!
   Rooster - Monday, 06/10/02 02:12:59 GMT


You need to check the member's forum. (grin)
   Paw Paw Wilson - Monday, 06/10/02 02:41:17 GMT

triple/ double temper
the Idea behind them is to reform some of the remaining austenite in to martensite. after hardining only about 75%-85% has been converted after the first temper (if held for over 1-1.5 hours) some (15% or so) of the austenite is re formed into untempered martensite the second temper cycle tempers this and adds a bit more martensite to the steel by the third cycle the majority of the crystals are tempered martensite. this results in a finer grain and a better edge holding ability along with a slightly better flexabilty.

a sword should be a bit softer than a knife thus temper at a higher temp. I temper most of my knifes betwine 325 and 400 deg. my combat swords are made from 5160, and I spec them at RC50-55 (depending on the blade)(I send them out for now, untill I get the equiptment to do a better job than my heat treater) one exception to that is kung-fu draw cut swords I have made those were edge quenched and tempered down to 55-58 or so (for better edge holding.)

I am allmost sorry I missed the malcontent.. he got such a reaction from all of you.(grin) then again after two days af BAD jokes and insults at the renn fair this weekend maybe not.(Big grin)
   MP - Monday, 06/10/02 03:01:45 GMT

Steels: 888, Spring steel varies in carbon content from 60 to 95 points. Tool steel generaly starts with 95 points but you can make "tools" from steels with much lower carbon (thus less hardenability). So spring steel is very good for making many tools as well as blades.

Truck and car axels tend to be 4140 or similar alloy. Many smiths make hammers and punches from this steel. It is a tad soft compared to tool steels but works well as long as you are hot working mild steel.

Old tools are very good "scrap". You can recycle old hammers and sledges, big old cold chisles. Pry bars are commonly made of 5160 which due to the alloy content is deep hardening. How many old lug wrenches can you scrounge from the local auto scrap yard? They are all tool steel of some sort.

True tool steels hold up to heavy abuse and the hot work steels hold up better for hot cuts and punches.

The best thing to do is study, experiment and learn from doing. The thing about much scrap is that is costs almost nothing compared to new tools steel.
   - guru - Monday, 06/10/02 03:03:45 GMT

Aw gee MP, They didn't tell you about "how long it takes to look at a horseshoe" 10,000 times. . . and still expect you to laugh?

Chris, It COULD be a big cold chisle OR a wood splitting maul. . . Most of the mass is in front of the eye in these.

Wellll. . . I sucessfully got a second HD installed in my aging PC and now its time to replace the CD so I can processs all those ABANA photos we are expecting. . .

   - guru - Monday, 06/10/02 03:10:07 GMT

I am fairly new to the blacksmithing trade and work at a historical village as a blacksmith. I was wondering if you could give me any tips on forge welding as any modern types of welding are not avalable to me.
   James - Monday, 06/10/02 04:33:23 GMT

James, See our iForge demos on forge welding. They cover most of the points you need to know. Practice is the only thing that makes it easier.
   - guru - Monday, 06/10/02 06:05:13 GMT

Thanks Bob, u've been a great help:D

I really appreciate all the help everyone has given me, this information has given me a much straighter line to follow:D
Thanks ALL!!
I still don't know about sticking a sword into a live person:S that's just plain sick:(, maybe a dead cow?:P joking!
Anyway...did i miss something about an anti-socialpath?? I'm only 16...is that old enough to hear his trash?
   Nicholas - Monday, 06/10/02 10:39:58 GMT


You've probably already heard as bad or worse, but there's not real need to repeat it, and it certainly didn't belong in this forum.

Guru took care of it, probably best to let it go at that.
   Paw Paw Wilson - Monday, 06/10/02 11:30:11 GMT

Live Quench or Testing Nicholas, There have always been myths, jokes and rumors of using live subjects for sword testing in ancient times. But there has never been any historical proof or evidence. These are simply fantastic stories used to amaze the uninitiated and over the millenia they have tended to be the same. In fact we had a long tounge in cheek discussion here several years ago about using lawyers for modern test subjects and agreed that "with briefcase" was the best test.

Swords tend to be associated with all types of myths and legends that spark the imaginaginations of young men. Otherwise you would have no interest in making a weapon that is of no practical use in this era. But they are just stories.
   - guru - Monday, 06/10/02 14:44:18 GMT

Hammer question
Chris it could also be a rail cutter they were used to score the rail (railroad rail) and then it was lifted and dropped to snap it.
   - JimG - Monday, 06/10/02 14:53:51 GMT

sword tempering and myths,
I once spent a fair bit of time educating this lady at a demo once about how important blacksmiths were, that they generaly were intellegent, that they usualy were well respected in the community. I went on to mention the amount of inspiration the smithy has been for poetry, stories, how if is wasn't for the smith we'd all still be in the stoneage etc. I could tell from the look on her face I'd given her a lot to think of she was seeing us as more than horseshoers and drunks (apoligies to drunken horseshoers) and then the guy who was helping me told her about tempering swords in slaves. I realy wish I'd had a sword to harden and temper at the time.
Thinking about it, it doesn't make sense to me. If the blade was hot enough to harden when quenched, wouldn't it be too soft to go into a body?
All it would need to do is glance off a bone or something and end up bent?
While talking about demonstrating.
Please be very careful when talking about forge welding and do not mumble when saying the word 'flux'........
I learnt that the hard way too.
   - JimG - Monday, 06/10/02 15:06:50 GMT

Jim G.

Chuckle, I can understand what happened. I once made that mistake talking to my wife. She told me what it had sounded like, so I no longer say "flux", I now say "welding flux". Keeps me out of trouble. (large grin!)
   Paw Paw Wilson - Monday, 06/10/02 15:24:34 GMT

Jim, I like the method used in Conan the barbarian, compare the color to the sunrise and quench in a soft fresh snow bank. . . . very poetic.

The fluffy snow used was too low of density to even equal a warm oil quench. . . but it WAS poetic.

   - guru - Monday, 06/10/02 15:38:30 GMT

My Lincoln AC buzz box has made hundreds of dollars worth of anvil tools (including Hardys) and several times that worth in various shop fixtures that I welded up out of scrap. At the time, I hesitated to shell out $200 for the welder. Soon after I got it I was kicking myself for having waited so long to buy it.

In addition to a welder you will need some way cut heavy stock and tool steel. An abrasive cuttof wheel or a HF bandsaw runs about $175

I have heard several experienced smiths say that the first piece of equipment one should get is actually an oxy acetylene torch because with that you can weld and cut and heat. Makes sense to me and I think if I had it to do over, thats the way I would go. A good basic torch set costs about $200 plus tank rental.

One guy working alone w/o power tools CAN hammer out an anvil tool, stem and all, from tool steel but its a lot of hard work and your arm wont want to do anything else that day. You wont make many tools this way IMO. With basic welding and cutting equipment it's a matter of an hour or two of easy work.

   adam - Monday, 06/10/02 15:59:49 GMT

As for the foulmouth who visited here, Sic'em Guru! Regarding the hot strength of steel, 4130, a Cr-Mo alloy, has surprising strength at 2000F. Our research came up with a strength of about 10,000 to 15,000 psi, enough to go through a body I would think, even though it would drop slightly at proper forging temperature.
   Quenchcrack - Monday, 06/10/02 17:27:45 GMT


If I have a plate of steel 6" thick cut on an automated burning unit, to what depth will the surface be hardened? Will this exceed the variation in the surface texture?
Third question
Finishes for ironwork have often been discussed here. Is there a paint that is thin enought not to obscure texture and fine details of forged ironwork?
   Patrick Nowak - Monday, 06/10/02 20:56:05 GMT

Ok, I checked out the issue of retained austenite in one of my Ferrous Metallurgy books. It says retained austenite transforms mostly to ferrite(pure iron) and carbides (iron and carbon), not martensite. In low alloy tool steels (W1, O1, etc.) this happens between 392F and 572F. In high alloy tool steels (H13, D2, etc.) this happens at temps in excess of 932F. If some small amount of retained austenite does transform to martensite, the second temper will reduce its hardness. Triple tempering may be applicable to high alloy tool steels but it does not appear to be necessary for the low alloy steels. Apparantly, if your second temper is not above 392F on low alloy or over 932F on high alloy, it is not really doing any good.
   Quenchcrack - Monday, 06/10/02 21:58:12 GMT

Plate Cutting: Partick, My experiance with machine cut heavy plate is that almost no hardening occurs at all except new the top corner of the kerf. But the degree of hardening depends on the type of steel and how well adjusted the cutting machine. Good flame cutting has an almost bright scale free finish and this is more common on heavy plate. I've built machine components from up to 8" A-36 plate.

You question about detail is a matter of scale but any PROPERLY applied paint hides nothing. Imagine the slitest flaw or crease in your shiny new car's finish. A good automotive finish (if it doesn't have that crummy water based clear coat) will last 20 years.
   - guru - Monday, 06/10/02 22:27:17 GMT

regards finishing steel (iron) work. There is a product called POR15. I think it is a moisture cured urethane. The stuff just loves rough surfaced or rusty steel, brushes well, requires no primer, and seems to be bullet proof. I've used it on auto frames for a number of years and it's holding up like new. It comes in gloss or semi gloss black, silver, and clear. When you apply it wear latex gloves because if it dries on your skin it's there untill you wear it off. cost isn't too bad about $30 per Qt. but it's thin and it goes a long way.
   bbeck - Monday, 06/10/02 23:14:49 GMT

most heat treating refferances are based on a 1 inch square of said materal in thiner sections the metallurgy dosn't change but it can and will react in a difererant manner. like W1 being a water hardining steel in a knife sized cross section will crack 80% od the time in water but will get full hard and not crack in oil.

my last post is the jist of what I have read over the last 3 months or so along with a good deal of help from a professional metallurgest that was kind enough to expain the stuff I got lost on. I am verry sorry if I was wrong.
how ever I have proved the worth of the triple temper to my self with my own testing and can honistly say it works very well for every steel I have tested. gaining in flexibilty and a reduced grain size (alowing for a keener edge and longer edge retention) granted I don't nomaly work with simple carbon steels nor the HI alloy tool steels, mostly 5160, O1, A2, and W1.
however IMO any reduction of retained austenite will benafit a blade.
   MP - Monday, 06/10/02 23:57:25 GMT

guru, et al, need rec on a stock shear, manual operated, capacity 1", for mild steel. thanks again for the expertise.
   - rugg - Tuesday, 06/11/02 01:12:21 GMT

Foul mouth // low life // from Ottawa On.
Looked up the address using www.canoe.com
La Cité Collegiale,
"Collège d'arts appliqués et de technologie"has 2 campuses in Ottawa and several others at venues around Ottawa. (the main one is at 2465 St. Laurent Boulevard.) The aviation Boulevad site is another campus that seems to have an 800 number. Namely, 1 800 267 2483. I don't know if that number works from the U.S.
I hope that information is of some help.
P.S. Testing a newly forged sword in a lawyer might cause the local State Bar to Take issue. Perhaps even sue for negligence (especially if the blade broke). I am certain that they would strenuously object if you did not pre-purchase the required licence. (from them, and I bet it would cost plenty $). Also, what do you propose to do with the ensuing toxic waste? Chew on that one for a while.
Regards to all.
Attny. at Law (N.Y.S.),
Barrister and Solicitor (Ont.).
   slag - Tuesday, 06/11/02 02:18:26 GMT

Back from Boston, New Bedford, and Saugus Ironworks NHS in Massachusetts. Saugus is an amazing site. Once I get the pictures developed, I'll do a feature on them and Hopewell Furnace (our other great ironworking site) if the Great Guru thinks it would be of interest. Fineries, chaffery, and 500 # trip hammer, with working waterwheels. Plus a rolling mill (stand back, Blue Crusher) under repair.

Well worth the trip, if hard to find. www.nps.gov/sair/
   Bruce Blackistone (Atli) - Tuesday, 06/11/02 02:24:50 GMT

Rugg, Generaly 1" bar is beyond the capacity of a maunal shear. 1" diameter takes 24 tons to shear and 1" square 30 tons.

Roper Whitney sells an angle shear for 2" x 2" x 1/4" angle that has optional bar dies but their web site doesn't give specifics on the bar die size. You would think that if you could shear the angle you could shear 1" bar. However, the angle shear uses a progressive cutting method that doesn't shear the entire angle at once.

Also note that even with compound leverage this kind of shear must be anchored such that you can apply your full weight on a LONG (6 foot) handle. This usualy means bolting to a steel plate then anchoring that to the floor or a low bench also anchored to the floor.


   - guru - Tuesday, 06/11/02 03:39:52 GMT

Nah; You can make whatever you need yourself, been done for thousands of years.
For example a hardy....take a section of truck leaf spring and fold one end over lengthwise to fit your hardy hole or roll the end up lengthwise and forge square to fit. Forge a tapered edge on the other end. Use a fast taper for a cold cut and a long taper for a hot cut hardy.
A flatter from another section of the spring can be a short flat part with the other end forged out into a long skinny handle ( to absorb shock). And so on. You learn some new stuff and award yourself a new tool..cool
Honorable Slag an attny? oh law law , wouldn't a guessed.
   - Pete F - Tuesday, 06/11/02 06:47:55 GMT

MP, One of the reasons I enjoy coming to this site is to learn the "hands-on" side of basic metallurgy. Sometimes the theory and the practice seem to diverge. Blacksmiths are about the most clever, innovative people I know and have solved metallurgical problems for thousands of years before we knew the science behind it. If double or triple tempering works for you, don't change anything because the book says differently. You can't argue with success!
I was surprised to learn you had cracking problems with W1. I have been making carving knives forged from 1/4" W1 rods and water quenching them to Rc 64! A 425F temper for 30 minutes brings them to Rc60. I have cracked only a few blades and that was due to my less-than-perfect grinding after forging.
   Quenchcrack - Tuesday, 06/11/02 12:38:16 GMT

Rugg, I was browsing the "used tools" section on walace metal works, and they have a buffalo bar shear listed at 1 and 1/2" round or 1 and 1/4th inch square.
   Mattmaus - Tuesday, 06/11/02 16:22:01 GMT

Cracking on quench. This occurs most often when a piece is overheated when quenched or unevenly heated. Oil quenching helps prevent cracking when overheated. Forging steel that is too cool can also start cracks that show up later.

My references on double tempering simply say "some benifit in particular steels" and don't mention the progressive temperatures. The double temper with a low then a higher temper just goes to show how important temperature measurment and control is to getting the best results.
   - guru - Tuesday, 06/11/02 18:46:45 GMT

I've got one of those NC Forge Whisper Daddy 3 Burner forges on which the back panel insulation around the rear door has become quite cracked with sections falling out. This is especially true for the very thin section under the rear door. Seems like using rigid insulation with a big hole in it is a design flaw and I'd like to correct this by replacing the back with "Kaowool" or a like material. Any council or material source recommendations for doing this?
   Paul Howard - Tuesday, 06/11/02 18:47:46 GMT

can i heliarc weld with my plasma cutting machine?
   tom hassett - Tuesday, 06/11/02 19:05:28 GMT

Paul, I use a NC 4 burner and it was in use for only a few days when it started doing the same thing. I just replaced the rigid insulation plug that fits in the back door hole and stuffed it with Kaowool. I have been using the forge this way fo about 3 years now with no other proiblems.
   - Bruce R. Wallace - Tuesday, 06/11/02 20:12:10 GMT

Paul, The insulation on some NC-TOOL forges is actualy rigidised Kaowool board and others are Kaowool blanket. Neither is very durable. They are used because they are very light weight and efficient.

There are various patching refractories that can be used to repair your forge.

Daryl Richardson of Canada says:
I use an A.P. Green product "grefpatch 85" this is a high alumna product about 83-85%, it is also a premixed product and comes in a 55# pail. . . . After the mortar is dry I
spray ITC-100 on the whole in side of my forge, and forge doors. . .

ITC also sells a patching compound called ITC-148 that is recomended to use in conjunction with ITC-100. Let me know if you want a quote. We have ITC-100 in stock and are looking into inventorying the patching compound.
   - guru - Tuesday, 06/11/02 20:23:20 GMT

HeliArc (tm) and Plasma Tom, No, these are two entirely different things even though the equipment is similar. If you could do both the instructions that came with the machine would say so. There ARE multi-function machines on the market but they are not very common. There are also power supplies designed for universal use but the attacments are different.

Check with your weling supplier or the manufacturer if you don't have the machine instructions.
   - guru - Tuesday, 06/11/02 20:29:19 GMT

Jock, I can't get to the page to put in info for credit card to renew CSI membership, am on a Mac, would that be the cause of problem ? I tried two different days last week and a couple time today.I even tried going to the store and had same result.
   Tom-L - Tuesday, 06/11/02 20:40:30 GMT

Mac's: Tom, I don't have a clue. I know our sales pages currently have a routine that tests for browsers that support secure server connections with post Y2k verification and it has some Mac identification code but I'm not sure what it does. . . Apparently it doesn't do right.

I've removed that code. Please try again and let me know what happens.

CSI Sales/Dues Form

If I EVER get our new store system on-line it should fix many of these problems. . .
   - guru - Tuesday, 06/11/02 21:19:09 GMT

Hello, my name is broeders kevin and I live in Belgium (europe). I am in my first academic year of forging !!
I am working with my fellow students on a mirror with several ornaments which must be gastronomical objects ( vegetables and fruits). I was wondering if you could help me where I can find such examples, or if you have some techniques to help me !!
   broeders kevin - Tuesday, 06/11/02 21:34:51 GMT

most offten happens with thin long blades (daggers/ skinning knifes) and allmost all the time with the ruff style I was makeing for a bit (forged blade with nothing ground but the edge.) the real trick is that I used to water quench O1... untill some one told me that wouldn't work. soon as I heard that I started cracking 3 out of 5 blades... could only do it when I didn't know any better I guess. (grin)

Broeders Kevin
check out the Iforge page there is a demo on a few things that my be of help to you, the apple could allso be made to resemble a pare or an orange (I made one that looked like a pare ..thought I didn't want it to!!)(big grin)
   MP - Wednesday, 06/12/02 01:41:06 GMT

am looking for a 12" dia. 24"-36" long piece of cold rolled.
needs to be located in N. California can anyone help me out.
thank you.
   francis - Wednesday, 06/12/02 01:48:23 GMT

guru and Mattmaus, thanks for the shear info.
   - rugg - Wednesday, 06/12/02 01:58:05 GMT

Guru, I would like to know what size stock a Edwards #10 shear is able to cut, round, square and flat stock.
Thank you
   - Robert - Wednesday, 06/12/02 02:15:38 GMT

Francis, Good luck. I spent a year asking around for a piece of 18" round. . THEN had to find someone to saw off the ragged air arc cut ends. . . And now need to find someone local to cut the piece again. . its 5" to long!

Ocassionaly big scrap yards get stuff that size, most often from scraping ships. Occasionaly big industry has stuff that size but its far and few between.

Post you notice on the V.Hammer-In it will be seen longer.
   - guru - Wednesday, 06/12/02 02:41:22 GMT


No one makes 12 inch cold rolled. You might try E.M. Jorgenson steel. Up here they have rounds up to 48 inch and more. Mosly comes "rough turned" in these sizes. Or if you must have a nice finish, TG&P (turned, ground and polished).
   - grant - Wednesday, 06/12/02 04:21:04 GMT

Guru, On 6-10-02 you mentioned a product called POR15. The local auto parts store that sells paint was not familiar with it. Can you tell us the manufacturer or where it is sold? Thanks
   - Coalforge - Wednesday, 06/12/02 04:36:39 GMT

Hi guru
I have a number of slits to make in 33mm round bar, Ive done a couple but I appreciate any tips you can offer. Mainly on slitting chisel size shape etc, Im using H13 and the cutting part is about 9mm thick by 22mm wide and about 40mm long all three edges are sharpened, Ive hammered this shape into 30mm round h13 bar, Im using my kinyon style hammer to do the slitting, which works pretty well, I can do the slit in 1 heat but the end of the chisel gets pretty badly deformed after doing that :) forgot to mention Ive tried drilling 2x 3mm holes in the bar first, either end of where the chisel will slit, this really helps to keep the cut centered. Have you or anyone else here, made a bottom die for a power hammer to allow hammering a drift or even a properly shaped chisel through a bar? What about using a hydralic press for slitting? Any tips tricks or magic spells appreciated.
   - Shane - Wednesday, 06/12/02 05:45:43 GMT

Try this URL : www.por-15.com
I tried it this morning and got to their site.
   Mark - Wednesday, 06/12/02 08:22:00 GMT

I was wondering about Didymium glasses. I read on a lapidary/glassblowing site that a person got some "Gold welding lenses" from a welding supply store for 5.00$, are these the same things as Didymium glasses, if not are they better or worse? Do you know of any other sources to get Didymium? I have to get 2 pair and thats about 75.00$, which is a bit much. Thanks a lot
   Adam Ophaug - Wednesday, 06/12/02 09:54:54 GMT

Adam - $75.00 for two pairs of lenses that will save your absolutely, totally, incontrovertibly valuable eyesight seems remarkably cheap, to me! I wear bifocals and pay about $350 for one pair of regular plastic lenses and frames.
   vicopper - Wednesday, 06/12/02 11:35:55 GMT

Adam, how much is your eyesight worth? Remember, you can walk with a plastit leg, you can work with a plastic hand, but you CAN'T see with a plastic eye.
   Paw Paw Wilson - Wednesday, 06/12/02 13:06:31 GMT

Vegetables: I've made a bunch of hot peppers from steel pipe---draw out one end by squaring and tapering as usual then use a spring fuller to fuller in where the stem is a bit above the square taper. There's a nice webpage on how to do this, ISTR it was R.Gunther's??

Spargle can be done forging solid stock with some careful chiseling.

wheat can be made by forge welding some rods together at one end and then braiding them and then flattening the braide witht the leftover ends as the tassles.

At one Quad-State there was a demo on doing repousse to two pieces of sheet metal, welding them together along the edges with a small pipe (brake line IIRC)welded in and then heated in a gas forge and *inflated* with compressed air to get a more 3-d representation---they used a bicycle pump to inflate it at the demo to show you didn'ty need an air compressor!

If you are allowed forge brazing peas forged out of small rod---small ball swage!---could be braxed into a pod made by folding sheet metal, cutting to shape and welding the ends then opening it with a chisel and adding the peas and forge brazing them in place

Carrots are a variation on the hot pepper---if you hot brush them with a brass brush you can get a golden colour and a bit of brazing rod forged for the stems can be patinated green...

My suggestion is to find an example you like and try stuff out.

   - Thomas Powers - Wednesday, 06/12/02 14:12:11 GMT

Thomas, I responded similarly by mail. Start with photos or samples and pipe works well for many shapes.

Didymium Lens Please note that these are designed to filter the light created by the sodium flare in a glass blowers melting furnace. They are not the correct filter for metal working using a torch or forge. Standard filter welding lenses are available for this.

Sunglasses NO MATTER HOW DARK are not filter lenses. They may let you see through the bright light but they WILL NOT protect your eyes from the harmful rays in the wavelengths that do damage. Filter lenses have specific chemical dyes that absorb the harmful wavelengths.

I recently caught a friend who should know better using sunglasses with a cutting torch. . . . NO, you only THINK it works. He had the proper welding goggles hanging it the shop. .
   - guru - Wednesday, 06/12/02 14:45:17 GMT

A friend? I think I know who you are talking about. Chuckle.
   Paw Paw Wilson - Wednesday, 06/12/02 14:54:15 GMT


eBay item # 2112311887

Got any idea what it is?
   Paw Paw Wilson - Wednesday, 06/12/02 14:57:01 GMT

Guru, in line with your previous post...

Do you recomend filterd lenses for work in a coal forge?

How about a gas forge?

Based on your previous post, I susspect the answer is "yes". In that post are you recomending Oxy-acetelene style goggles (like a shade 4-5) or does a person need more (like for mig welding I wear a shade 10)?

Lastly, as everything I've read, and seen at demo's and so on, most of a working smith's temperature control comes from the color of the steel or iron he's working on, how do the lenses affect that?
   Mattmaus - Wednesday, 06/12/02 15:05:00 GMT

Some smiths use filtered lenses and others do not. If you do a lot of forge welding you should, particularly if done in a gas forge.

The level of filter lens varies with the distance from the work as well as intensity of the source. Filters in the 2-3 range are used for flash glasses and in foundries so I suspect they are suitable for forge work. When gas welding or cutting your face is generaly close to the work so that you can see the puddle or into the kerf. So you need a darker shade.

Judging color temperature has more to do with ambient lighting than anything else. An orange heat in low light will just barely appear hot in direct sunlight and will appear to be a yellow heat in the dark. So, it is what you are used to seeing. Judging heat wearing filter lenses is the same. With practice you will know just as well as someone without filter lenses.

I just placed an order for the standard wire side shield safety glasses that I mentioned last week. We will be selling them in clear polycarbonate lenses and a #2 green shade (I'm taking a gamble here as the supplier had no specific recomendation).

The filter lens glasses will run $16/pair and the plain $10. Look for them in our on-line store next week.

I got a price on the Didymium glasses from my supplier and $75 for 2 pair is a good price.
   - guru - Wednesday, 06/12/02 16:55:06 GMT

will the standard wire side shield saftey glasses that you will be stocking go over prescription glasses.
   L.Sundstrom - Wednesday, 06/12/02 18:05:10 GMT

Great news about the glasses guru, hopefully I have money next week!
   Mattmaus - Wednesday, 06/12/02 19:52:32 GMT

Another query from way down south...
I am in the process of building a side blast forge with two tueyeres. (Overkill!) I also have a bottom blast forge. These will be linked to a single blower.
I need to know the volume of air the blower should deliver per minute or second (cu ft is fine) as well as the pressure in lbs/sq inch or kgs/sq cm it should have at the blower if the connecting pipe is 30' long and 4" in diameter with two 90 degree bends in the pipe.
I also need to know the optimum size for the hole in the tuyeres for these pressures and volumes.


Tiaan Burger
   Tiaan - Wednesday, 06/12/02 20:05:03 GMT

Ebay item. . . No, its not a blacksmith tool. Its a "hand anvil" for making standing seam or lock joint roofing. It goes with two pairs of hand bending tools that have reins and a joint identical to tongs and long flat jaws for bending. One or both pairs usualy has pins attached to one jaw that pass through the other to act as back stops or a depth guage.

SAFTEY GLASSES: No, they don't fit over prescription glasses. Sorry.
   - guru - Wednesday, 06/12/02 20:09:58 GMT

Tiaan, If you have an older copy of MACHINERY'S HANDBOOK the information is there. It is also in the Buffalo Catalog CD we sell. I'll look it up but I've got two deadlines this afternoon (Its demo night AND illustrations are due for the next chapter of Paw-Paw's book. . .). So I'll have to post it tomarrow.
   - guru - Wednesday, 06/12/02 20:34:36 GMT

Guru, thanks very much. I haven't seen a "machinery's handbook" in my life! I will take a look here tomorrow night. The steel for the forge will only be delivered by Monday and then I still have to weld all the pieces together. I will give the guy who is building the blower a ring tomorrow and tell him to hold on a while.
   Tiaan - Wednesday, 06/12/02 20:43:18 GMT

Dear Guru

I am starting my own smithy in the uk, and would like to construct my own coal fired forge and would like to find some plans of construction, however the only plans i am able to source is that of gas fired forges which is not what i want. Info especially on suitable tuyere is required.
   Matt - Wednesday, 06/12/02 22:46:03 GMT


Are You heat treating the chisels after you forge them? Does sound like you're getting them too hot, they should hold up for hundreds of holes before you need to dress them. Keep a bucket of HOT tap water for cooling the chisel, cold water will crack H-13 sometimes. Or keep two chisels handy so you can use one while the other is cooling (best way).
   - grant - Wednesday, 06/12/02 23:01:06 GMT


9 mm thick sound too thick to me. should be more like 6mm measured about 20 - 25mm up from the cutting edge, taper on the cutting edge should be no more than 20 - 25 degrees, less in back.
   - grant - Wednesday, 06/12/02 23:13:53 GMT

No Im not heat treating the chisels after using them, Im using a cutting chisel thats only about 80mm long, so I can fit it under the power hammer, this makes it very hard to remove, it goes nearly all the way through the bar but I this gets it too hot. I dont have any taper on the slitting chisel, its 8-9mm from behind the cutting edge all the way back to where the 32mm round bar part starts, bout 30mm or so, this way I thought all it does is cut and I use a drift for the opening of the hole.
I did try making a bottom die for the hammer yesterday that allowed pushing a drift right through the slit, worked great cept the bar being drifted got quite deformed by the pressure, these holes are only about 8-9mm from the end of the bar, so the 8mm part got pretty bent and crushed, drifted in 1 heat though with a 25mm drift. Im thinking if I made a bottom die with a hole in it thats about the same size as the drift I might be able to get this to work, then its a problem of putting the drift in the right spot. Can a power hammer cut or drift using a chisel as the top die and some sort of clamp system on the bottom die to hold the bar being slit and hitiing the bar with the chisel? or would the chisel mabey get lodged in there? just thinking out loud.
I will try a thinner chisel and hot water though thanks for the tips.
   - Shane - Thursday, 06/13/02 00:57:25 GMT

I don't mean heat treat after using them, I mean after making them and before using them. 9mm all the way down? Sounds more like a punch, what kind of bevel on the end? A thin wedge shape would drive easier and come out easier. I would do this with a bottom die shaped like a 40mm bottom swage, and slit 3/4 of the way from one side and turn it over and slit the other side. Then I would hammer on the end of the bar to open the hole and then drift to size.
   - grant - Thursday, 06/13/02 01:10:09 GMT

a good friend of mine was just killed in a industial accident with a grinding wheel i will never thing of a grinding wheel again
   terry tallman - Thursday, 06/13/02 01:10:15 GMT

That IS close to the end. Sometimes it pays to start with a longer bar, do the drifting and then cut the bar off to length.
   - grant - Thursday, 06/13/02 01:12:28 GMT

In regards to the glasses: Yes, obviously I would pay whatever cost, to save my eyesight, I was simply wondering if Didymium was the best to use? Jim Hrisoulas in the "Master bladesmith" says to use these with a propane forge, is he mistaken? No offense to him, but I'll take your experience, Guru, with gas forges over his, and your saying the welding lenses/glasses are the best? Thanks a lot
   Adam Ophaug - Thursday, 06/13/02 01:22:39 GMT


Didn't mean to be insulting, was just trying to emphasize the importance of proper safety gear, properly used.
   Paw Paw Wilson - Thursday, 06/13/02 01:31:43 GMT

Adam, There has been a lot of discussion about Didymium glasses and to the best of my understanding they are designed for the sodium flare of a glass furnace and that normaly you don't get this in a gas forge heating steel. HOWEVER, borax flux is full of sodium and you may get some sodium flare from it. . . BUT, borax is used as brazing flux too and standard #3 filter lenses are recomended for brazing and meet OSHA requirements as far as I know.

Didymium is a mixture of neodymium and praseodymium. In practice it probably has other rare earths present as well (with the exception of cerium). At one time the mixture was thought to be a distinct element.
- rec.crafts.metalworking
Didymium glass has been used for many years as a high wavelength visible
reference material.
- www.optiglass.com
Glass workers and Metal workers Protective Eyewear
Rose Didymium:

This is the classic filter that has been used for
many years in all types of hot glass applications, as well as kiln working. The lens is dichroic (exhibits different colors under various light sources). Under incandescent light, the lens is a pronounced rose color, but changes to greenish blue under fluorescent light.
Suggested uses are: Beginning lampworking using hot head torches and MAPP gas, or propane torches with soft glass. Acetylene torch work on silver and gold jewelry, enameling of jewelry, and any operation requiring occasional viewing of heat sources in excess of 1000°, but not for use with high pressure torches on hard materials where very high temperatures are generated.
- www.auralens.com
In general, this filter is adequate for most art glass blowing applications, and can be used in poorly illuminated shops, since the visible transmission is generally adequate. (It is not dark glass) These rose didymiums filters out sodium flare at 575 to 600 NM.
- www.artglass1.com
I get my gasses from a welding supply and when I was there picking up some oxygen the sales guy pulled out a gold coated rectangular welding lens. It is made to be sandwiched between two pieces of glass in a welding hood. I use it for platinum minus the hood and glass. I can clip it to my third hand and and keep it in place while my other third hand holds the platinum piece Iam working on or just mount it in an old optivisor if you have one. The gold film is rather fragile that is why it should be sandwiched between glass and if the gold film is scratched your eyes are not protected from the torch. The lens cost me $5.00 .
Here is the full poop on how to get info about the gold didymium lenses. Mr. Schell sent this reply to my query. If anybody wants to pursue it this leads the final word. Geo.

In 1995 I contacted the National Institute for Occupational Safety and Health (N.I.O.S.H.), which is a division of the U.S. Department of Health. NIOSH conducted tests in my studio for two days and subsequently prepared a compehensive report that includes the gold coated didymium II lenses, Aura lenses and more. The report, which was published by the U.S. Government, includes graphs. It may be purchased by contacting: National Technical Information Service (NTIS), 5825 Port Royal Road, Springfield, Virginia, 22161. You should request the NIOSH Health Hazard Evaluation Report, HETA 95-0119-2554. It is titled, Glass Schell Fused Glass Masks, Houston, Texas. It was prepared by: C.Eugene Moss, H.P., C.S.S. and Gregory A. Burr, C.I.H. If you have any difficulty getting the publication, you may call NIOSH at:
800-356-4674 Thank you, JIM SCHELL
- www.ganoksin.com/orchid/archive

HOW HOT a furnace, torch or arc gets AND the material heated determines the wavelength of the light it produces. Didymium filters out primarily sodium flare and is not recommended for high temperatures. The primary advantage to these lenses is that they do not filter a lot of visible light but cancel out almost all sodium flare so that glass workers can see clearly. The manufacturer quoted above does not recommend them for high temperature metalworking.
   - guru - Thursday, 06/13/02 03:34:01 GMT

Jock, sorry to bother you again, I was just curious as to what sort of glasses you use while forging? thank you
   Adam Ophaug - Thursday, 06/13/02 07:04:10 GMT

I have a fascination with swords and making them, I've been looking for a while now trying to gather information so that i may be able to forge my own swords. My main dilemma is on how to build a forge to do this, and how I can go about doing so, preferably using old methods. If you can help me with this, it would be greatly appreciated.
   Robert - Thursday, 06/13/02 07:36:11 GMT

Robert, after forging a number of blades and sweating putty balls trying to keep the blades straight, I would suggest you just buy a sword and lie about where it came from! hehehe...
   Quenchcrack - Thursday, 06/13/02 12:04:24 GMT

Safety Glasses: Adam I normaly wear regular safety glasses for forging. But I never ever weld (gas - arc) without proper eye protection. But I don't do a lot of forge welding so I don't spend much time looking into the heart of the forge fire. And that is where the problem comes about. On its surface a forge fire is no brighter than a camp fire. But at the heart of the fire where you get a welding heat it is much different and so it is with gas forges.

Time, distance, temperature and intensity are the variables in this equasion. You won't go blind from an occasional glance at an arc welding spark. But you can do great damage to your eyes looking closely for just a few seconds. The high infrared from a white heat can cause damage from chronic exposure. However, time, distance and intensity
are critical variables.

In this case intensity would have to be a measure of surface area. A white hot piece of finger sized bar has little surface area compared to the glowing interior of a gas forge. But distance is also a factor in intensity. That small piece of bar at arms length is equivalent to a one foot square forge opening 25 feet away.

Time enters into the equasion in two ways. That white hot steel bar cools rapidly becoming less intense a radiation source AND the character of the radiation changes with the temperature drop. But the gas forge you are staring into remains relatively constant.

And THERE is the problem. Staring into a hot gas forge trying to determine if you have a welding heat. . . You are close to the forge, it is very large (intense) surface area AND you spend too much time peering into the hottest part.

. .focusing on glass workers and studying the infrared end of the spectrum, Lydahl and her associates (Lydahl & Philipson, 1988; Lydahl and Glansholm, 1989) compared their 200 glass workers with an age-matched control sample of non glass workers and found an association between infrared exposure and the presence of cataracts. (Interestingly, they also found much more damage to the left eyes of glass workers as compared to their right eyes, a difference not found in the control patients. The authors interpret this finding as caused by the usual "right-handed" arrangement of most glass shops which puts the left eye closer to the furnace and glory hole.)

The literature concerning the actual biomedical processes that cause eye damage is complex, often confusing, and sometimes contradictory. Despite that, though, the general themes of the results are clear enough:
  • Exposure to infrared and ultraviolet radiation is likely to cause ocular damage, primarily from absorption of radiant energy and its subsequent transmission to the lens where cataracts are likely to form.
  • The more the combined lifetime exposure to infrared and ultraviolet radiation, the greater the likelihood of ocular damage.
  • The exact mechanism of the damage, its exact location, its permanence, and its severity all depend upon the specific wavelengths, intensity, duration of each exposure, and life-time total exposure, along with other factors.
  • Appropriate filters and awareness of the potential hazards can minimize exposure and help to prevent nearly all damage.
- www.fandm.edu/departments/Psychology/Eyeprotection/Hazards06.html
The above article focusing on glass working goes on to recommend #3 shades for glassworkers, the same thing recommended for gas brazing.

The life-time exposure includes many sources of UV and IR including sunlight. Thus age, lifestyle and environment become a factor as it does in many other areas.

   - guru - Thursday, 06/13/02 13:50:47 GMT

Coalforge....Source for POR15 rust preventive coating. Maintence Specialties Co. 800-777-6715. www.rustpaint.com they are in New Castle, DE.
   bbeck - Thursday, 06/13/02 15:11:47 GMT

Guru, Maybe you missed my question the other day? If I missed your reply I`m sorry but did look over the posts after that several times. What size of round, square and flat stock is a Edwards #10 Shear able to cut, maybe factory specs. if you got them. Thank you
   - Robert - Thursday, 06/13/02 15:14:28 GMT

Just a thought about eye protection. In our rolling mill, the steel slabs are heated to about 2200F. This is not quite welding temperature but very close. Most of the furnace operators use a cobalt blue lens that flips down from the brim of the hard hat. It will allow you to look into a white hot furnace and clearly see whats going on. Don't know if an industrial supply would carry these or not.These are not side-shielded so they are used in conjunction with regulation eyewear.
   Quenchcrack - Thursday, 06/13/02 15:50:03 GMT

NOTE: Work habbits are another factor that is hard to define in personal safety and they can make a big difference.

The experianced smiths that I know that use coal spend very little time peering into the fire. The coal and coke on top of the work also shields one from much of the glare.

When forging small work with my NC-TOOL forge most work gets done through the little notch in the door and I rarely check the work by looking into the forge. In my big forge which does not have the convienience of a door I usualy block the front opening down to the minimum. When I DO need to look inside I keep the glimpse short.

In occupations where you can't look the other way or the area of intense light is unavoidable such as in foundries then full time, full range eye protection is required all the time. The problem in the small blacksmith shop is that we do such a wide range of things that we need to be constantly changing our personal safety equipment and eyewear is one of the most variable.
  • General shop use, Clear side shield glasses.
  • Small grinders, Clear side shield glasses.
  • Heavy grinding, clear safety glasses AND full face shield.
  • Forging and under hood flash glasses, #2 shade
  • Brazing light gas welding #3 shade
  • Cutting heavy welding #5 shade
  • Arc welding #10-#14 shade depending on size/amp.

"Flash glasses" are relatively lightly shaded glasses (1.7 to 2.5 shade) worn in the shop to protect from arc glare from other workers. They are also recommended to be worn under a arc welding hood. These reduce the damage caused when you accidently flash yourself and from reflected arc light. They also provide secondary protection against sparks that get under the hood.

   - guru - Thursday, 06/13/02 17:16:36 GMT

Does anyone know where CanIron IV is to be held in '03?
   Ralph - Thursday, 06/13/02 17:34:32 GMT

Ralph. . I forget the city but its going to be close to Detroit just across the border. I have yet to see details on dates and such.
   - guru - Thursday, 06/13/02 18:08:48 GMT

Edwards #10 Iron Cutting Shears:

Cuts mild steel 4 x 3/4" and 6 x 1/2" flat and 1" round. Knives 7 inches long. Weight with handle 486 pounds.

$120 in 1955 - Industrial Supply Corp Catalog, Richmond, VA.
   - guru - Thursday, 06/13/02 18:25:22 GMT

Air Pressures and Pipe Sizes for Forges Tiaan, I converted the MACHINERY'S article to HTML and posted it on our FAQ's page. It requires some math to use.

I'm also still looking for CFM but the general range is 50 to 500 CFM. The forge blowers that Kayne and Son sell range from 65 CFM and 14oz. to 400 CFM at 74oz.
   - guru - Thursday, 06/13/02 20:03:30 GMT

Thanks for the info, I made a printout of the table. (The first place I looked when I started my search was the FAQ page!)

I have a blower that gives a decent fire (fine for small work up to 1" x 1" rod) on my old forge. I stacked paper of known weight on top of the fire pot until the stack did not lift under full blast. A very rough method which gave me a reading of about 5 pound per sq inch! I realised that this couldn't be right after the guy at the "fan shop" told me that the fan would need a 11KWatt motor to provide 15 cu ft at that pressure!

   Tiaan - Thursday, 06/13/02 20:27:08 GMT

Ralph & Guru

CanIRON IV is being hosted by the Ontario Artist Blacksmith Association (OABA) and is being held at the McMaster University Campus in Hamilton, Ontario Canada in July 2003.


   Mark P. - Thursday, 06/13/02 20:56:14 GMT

Thanks. I was hoping it would be a tad closer. So I guess I will not be able to go.... ( frown)
   Ralph - Thursday, 06/13/02 21:56:18 GMT

Guru, I am still trying to make some simple anvil tools and today, I found some 1-1/2" 4130 plate. I cut off two pieces about 1-1/2" square and 4" long. I planned to forge a fuller and a hot chisel but after taking a second look at the section size, I am not sure I will live long enough for my Whisper Baby to heat it up. What do you think? Should I take them back to the machine shop and saw cut the reduced section?
   Quench Crack - Thursday, 06/13/02 23:29:03 GMT

Quench Crack. . time for a bigger forge. . . and maybe a power hammer. 1-1/2" 38mm stock is BIG stuff in alloy steel.
   - guru - Friday, 06/14/02 00:21:35 GMT

I am a 25 year old art student. My main medium is oil paint on canvas. I am interested in using copper sheets as support for my oil paint. I have never worked with metal before and I am not sure where to find the material. I would also like to create pantinas on the copper and then cure it and seal it somehow, so I could paint on it. Are there particular acids I could wash the copper sheets with to create pantinas or do I have to use a torch? Your insight and resources concerning this matter would be quite helpful. I would also like to know about the techniques and dangers of copper patination. By the way, I live in Upland, CA- which is in Southern California.
   Candice - Friday, 06/14/02 07:09:20 GMT

Even the reasonable level of eye protection our Good Guru puts forth leaves some inevitable room for vulnerability..certainly enough to satisfy a need for a little risk that so many of us seem to peversely have..
For example, wearing the recommended glasses with side shields while using a small grinder, I managed to imbed a piece of steel in my iris firmly enough that it took about 15 uncomfortable minutes with a little haemostat in front of a mirror to finally pull it out. Being single then and a long way from town, there was no available help. Went blind in that eye for a couple of days and it was pretty vivid. I didn't like that part.
In contrast, in the Weigers book, he says that professionals just learn to squint while grinding.
   - Pete F - Friday, 06/14/02 08:18:30 GMT

Protection: A few weeks ago I finaly bought the full kit. It´s a full face-shield with over-pressure provided by a filter-fan-battery unit carried an a hip-belt. A flip down visor with automatic darkening glass makes it a welding helmet as well. It´s not for forging, but for everything else. My forge is smoke free, it´s the point ventilation for grinding and welding that´s lacking, but since I only rent the forge a portable unit makes sense to me.
   - Olle Andersson - Friday, 06/14/02 11:17:34 GMT


Where did you buy that unit, if I may ask?
   Paw Paw Wilson - Friday, 06/14/02 11:34:48 GMT


Some of the most delicate works I've seen are paintings by the numerous Brueghel family, done on copper. (try: http://www.nga.gov/cgi-bin/pimage?110593+0+0 for example)

In truth, I don't know the method, but I certainly admire the results. If the the Great Guru or my fellow lesser gurus at this site are left collectively scratching our heads, you might try the National Gallery of Art at: http://www.nga.gov/ The staff has been more than helpful to me in the past.

Now, for a flying guess: I would try polishing the surface with the finest steel wool, and painting directly on that, being careful not to touch the surface with my fingers. The oil paint (probably thinned a bit more than usual, looking at the originals) should seal the surface from corrosion. (But this is only a guess.)

Patination of copper, on the other claw, is one subject where I know the Guru can help you. Good luck, and let us know how it goes.

A rainy day on the banks of the Potomac.

Visit your National Parks: www.nps.gov

Go viking: www.wam.umd.edu/~eowyn/Longship/

   Bruce Blackistone (Atli) - Friday, 06/14/02 13:46:24 GMT

Pete, it may be the shape of your glasses, I used to wear the (for lack of a better description) "blade" style glasses. They were what I was issued at work, and were comfortable enough. At work I wasn't doing any grinding tho.. I was at home, and discovered that the glasses protected well from front top and sides, but the way my head is shaped, left a big gap in the bottom, that let a lot of sparks/filings/danger in.
   Mattmaus - Friday, 06/14/02 13:51:12 GMT

Eye Protection: As Pete points out much of what we use is a compromize. Most safety glasses leave gaps. If you want a perfect fit then you are going to need to go to two piece goggles or form fit singular goggles. These have soft plastic or rubber sides that conform to the face and do a VERY good job. I've used both and don't know why we don't use them more often. Perhaps its the elastic strap. They are no different than the goggles I use for gas welding.

Much of this has to do with what we are used to or are forced to do either by employers or self preservation. An astronaunt wouldn't go into space without his helmet and space suit. The reasons are obvious. But when the hazzard is transient we get complacent about wearing protection. We get away without too often and forget that the results of something that happens once in a thousand times may be with us for the rest of our life. It is human nature. But like other "natural" inclinations we must train ourselves differently. For those of us that work in our own shops it is often difficult.

Paw-paw, Olle is in Sweden and his sources are not likely to be of help to you.
   - guru - Friday, 06/14/02 15:24:47 GMT

Unless he ordered it over the internet, you're probably right. But doesn't hurt to ask.
   Paw Paw Wilson - Friday, 06/14/02 15:48:53 GMT

Paint on Copper: Candice, Copper is very chemicaly with many substances and it may react unpredictably with the pigments or oil in your paints. Today many artists have gotten away from the practices learned centuries ago of carefully preparing their ground so that the painting will last and not discolor, flake or peal. There are many modern works painted on raw canvas where the color of the canvas shows through and it is yellowing. . . Many of these pieces are in museums and the artists are now best known for their bad technique.

Modern commercial paint manufacturers make special primers to apply to active metals such as aluminium and zinc. These are often etching primers that have specialy selected pigments that do not react with the base metal therefore sealing it from subsequent top coats.

Any preparation of the copper, either clean and bright or patinaed should, at a minimum, be sealed with clear acrylic lacquer. This is not the best ground for oil paint but it will isolate the reactive oil paints from the copper.

A good durable patina on copper takes time or harsh chemicals. Naturaly it occurs from disolved CO2 in rain water which produces weak carbonic acid. This takes centuries. Among the common products available that will discolor copper are, bleach, some fertilizers, muratic acid (dilute hydrochloric acid sold to clean mortar off brick and masonary) and hydrogen peroxide. Sulphuric acid (battery acid, drain cleaner) is one of the best for coloring copper but it is also the one chemical you do not want to work with if you can avoid it.

Experiment on sample pieces. Some chemicals may need to remain on the surface overnight or for weeks.

Wear eye and skin protection (rubber gloves) when working with harsh chemicals. Work outdoors or where there is very good ventilation as strong fumes may be released. Bleach often releases chlorine gas which is lethal in quantity and damages the lungs in small amounts. NEVER, EVER mix bleach with other chemicals. This can release large quantities of chlorine gas.

As to shaping the copper see our FAQ on Repousse'.

   - guru - Friday, 06/14/02 15:55:54 GMT

does anyone know if cast iron can be brazed or does it have to be welded with ni rods
   888 - Friday, 06/14/02 17:50:40 GMT

Guru, Yep, I was afraid you were going to say that. Well, I will consider machining to shape and just hardening the end.
   Quenchcrack - Friday, 06/14/02 17:51:13 GMT

On a Silver Mfg hand drill press the bit is held in by a bolt screwed in the side of the chuck when trying to remove it it wrung off flat at the chuck. Tried a bolt extrator it didn't work so I tried another one it broke off in the hole flush of course. In the process of drilling it out I noticed that the hole had moved over from the original postion from where I center punched it. Now am I in as bad of shape as I think I am? At the moment all I can think to do is to abandon that hole and drill and tap another (forgot to mention that the chuck is cast iron). I should also mention that it had been soaking in Blaster for about 10 yrs. and I was heating the chuck when it broke the first time.
   Daniel - Friday, 06/14/02 19:50:26 GMT

I have a question on the exposure of your eye to Ultraviolet and Infra-red light waves. Are the damages cumulative and irreversible? For instance, the excerpt that was posted about a study done on glassworkers stated the damages were cumulative. Does this mean that if a person exposed to these sorts of light emissions takes, say a five year break and then starts up again the deterioration will restart where it left off? Or will the workers eyes heal for a period and then be damaged again?

Also, I am wondering about the type of lenses I wear for torchcutting. They don't cause light to appear green. They ARE safety glasses and they are darkened to about the same shade as a set of gas welding goggles but I'm not sure what the filtration consists of. If they are a darkened set of safety glasses do you think they are the ones with the proper absorbing dyes in the lens or could they be a cheap knock-off of a real safety lens? I just don't want glaucoma of cataracts I guess!
   Rooster - Friday, 06/14/02 20:03:29 GMT

It would seem that I posted in haste in that I found a way to remove the bolt with the torch however I need to drill and tap new threads can I do this in cast iron or am I going to have to weld a nut on the outside of the chuck for the bolt? Thanks for the patience and advice in advance.
   Daniel - Friday, 06/14/02 20:16:47 GMT

Paw Paw www.gemplers.com have what you want.
   Smitty - Friday, 06/14/02 20:45:39 GMT

Let's try this again Paw Paw www.gemplers.com has what you need.
   Smitty - Friday, 06/14/02 21:03:28 GMT

My "breather" is along the lines of the stuff found at the gemplers adress above, but far more compact and streamlined. At least part of it is made in sweden, but that doesn´t mean you can´t get it on your side ( like Volvo, Saab, Uddeholm and Sandvik steels.... well, those USED to be swedish anyway). I´ll check the exact model on the crate. It cost a bundle, though.
   - Olle Andersson - Friday, 06/14/02 21:27:40 GMT

If the chuck is indeed cast iron then getting a weld to hold against the strain a setscrew will put on it is nearly impossible. Drilling and tapping shold work if the meat is there.
   - grant - Friday, 06/14/02 22:23:35 GMT

888, Cast iron is commonly brazed and is nearly as strong as original. The choice to braze or weld depends on a lot of variables. Some shapes are nearly impossible to weld in cast iron due to shinkage and the resulting new cracks on the opposite side of the part. Even though brazing produces less stress the same precautions against cracking should be taken. Almost all welding references cover the procedure.
   - guru - Friday, 06/14/02 22:30:14 GMT

Drilling and taping cast iron is not much different than than steel except for the character of the chips. How do you think they got it taped in the first place?

As Grant said, pick a new spot and drill and tap. I'd take the spindle out and do it in another drill press OR make a clamp-on drill guide to be sure the hole is straight and true.
   - guru - Friday, 06/14/02 22:42:54 GMT

Does anybody out there know of any blacksmith's down in the south Texas region(preferrably SanAntonio) who will be willing to teach me some of the finer points of smithing?
   A.D. - Friday, 06/14/02 22:54:07 GMT

Rooster, All legal filter and saftey glass lens or frames are marked. Safety glass frames should have Z87 for ANSI-Z87 marked on them. All shaded lens for welding will have the shade number marked on the lens. If not it is not a ANSI Z87.1-1989 approved filter lens.
   - guru - Friday, 06/14/02 23:35:59 GMT

A.D. contact these people:
Pres: Jerry Achterberg
3318 Kirby Drive
San Antonio, TX 78219
(210) 661-3293

Ed: Hollis Wooldridge
7496 FM 482
New Braunfels, TX 78132
(830) 609-5105
These fellows represent the local ABANA chapter. It's a good place to start.

   Quench Crack - Friday, 06/14/02 23:49:53 GMT

my comment on welding the chuck were in reference to the idea of "welding a nut on the outside", seemed iffy at best. Brazing up the hole and re-tapping would have a good chance of success.
   - grant - Saturday, 06/15/02 00:17:38 GMT

Ralph,I don't know where you're from but,you should really try to make it up to Canada in July 2003 for CanironIV.Plan you're vacation around it!Come experience some good old Hamilton,Ontario hospitality.Everyone is welcome.
   Cookie - Saturday, 06/15/02 01:06:10 GMT

Daniel - Silver Mfg. Drill press repair

For a stripped-out bolt hole in cast iron, particularly one that is for a bolt that is used frequently like a set bolt for your drill press chuck, I would suggest that you seriously consider getting the right size Helicoil (TM) thread insert kit. That way you use the esisting hole, which makes drillling it straight much easier, and you get hardened threads via the spring coil thread insert.

Helicoil kits are available from your local auto parts house. The kit usually comes with the correct drill bit, tap and thread insert, plus a tool for inserting the coil into the new hole. They work particularly well in cast metals, since that is exactly what they were designed for.
   vicopper - Saturday, 06/15/02 04:36:20 GMT

To let you know, I bought some gold surface didymium safety glasses and a shield from Jim Shell a couple of years ago, but when I tried to contact him again after hearing that he had been gravely ill, was unable by phone or email or website to get through. Found the shields and glasses again at www.oberoncompany.com which is in New Bedford Mass. The safety glasses list at $24.75 a pair, and there are a number of different eye-safety products with literature on-line. I haven't gotten anything from them yet, but a couple of friends contacted them and got good service. Regards all...
   R.Whitehurst - Saturday, 06/15/02 05:30:42 GMT

Drill Chuck Cracked droped a note that made me think I had brain freeze. . .

If the "chuck" is an extension of the shaft then it is mild or medium carbon steel like the rest of the shaft.
   - guru - Saturday, 06/15/02 08:07:37 GMT

Copper As A Ground For Oil Painting

The Artist's Handbook by Ray Smith, published by Alfred A. Knopf 1996 discusses copper sheet as a support for oil painting. He notes that the sheet is best for small jewell-like apintings because copper dents easily and the dried oil paint film can be damaged where there is a dent.

He also notes that copper has a high coefficient of expansion. That means that heat causes the metal to expand and then contract upon cooling, a lot more than many other metals. A metal ground that expands and contracts is going to put stress on the over-lying dried oil paint film of the painting.

If you still want to use copper as the support Smith suggests the following method to prepare the copper surface. Prior to painting, a suitable ground should be applied to the copper surface. The copper should be thoroughly abraded with #180-200 emery paper abrasive. (in other words sand the copper surface thoroughly with the emery paper). Then the abraded surface can coated directly with white lead in oil, or titanium in a oil-modified alkyd solution. He notes that some artists suggests that the first coating of primer should be stippled onto the copper surface. Several layers of primer should be applied. The primer should be thoroughly dry before applying the next coat. He also suggests that the primer should be lightly sanded to remove any shiny surface on the primer.

The other bible of artist materials and techniques The Artist's Handbook of Materials and Techniques by Ralph Mayer, Viking Press, fifth edition. (there may be a more current edition, I will check), repeats the, above noted, points concerning copper's soft deforming properties and it's high coefficient of expansion. He writes that the paint film will blister or peel.

Mayer states that copper has been used as a support for oil and oil-resin paintings from early days (i. e. early 1440's), especially in Holland.

These 2 books are the standard reference texts for all manner of paints etc. and materials. The Mayer text was first published in 1940 and has been in print ever since. Northight Press has a similar book but I cannot remember the title. (an easy search on the Net). Try consulting those reference books at the local Public Library or Reference Library.

Hope that helps,
Regards to all the gang.
   slag - Saturday, 06/15/02 08:42:56 GMT

Im getting some railing powder coated soon and was wondering about whether a sealer primer was necessary over the zinc primer they apply, my p/coat guy told me they use a good zinc paint then powder over that but he wont guarantee anything, the customer is very worried about longevity so Im wondering about a sealer coat in between the zinc and the powder like when you paint steel, also can a double layer of powder coat help a bit too?
   - Shane - Saturday, 06/15/02 13:59:26 GMT

I would love to, but it is quite a distance from Portland Oregon. And I am not sure my wife would let our vacation be planned around CanIron... (smile) I was able to do that with ABANA 2000 but we also were checking out my daughters new school in Santa Fe at that time as well.....
Will have to see how things develop
   Ralph - Saturday, 06/15/02 15:02:37 GMT

Virus Hoax: Yesterday I recieved a virus hoax asking people to deleat a Windows system file with a bear icon.

The file is a legitimate Windows system file. The hoax is destructive. . there is no virus.

Please check the various anit-virus sites for hoaxes before fowarding ANY warning. Otherwise YOU become the perpetrator and just as bad as the virus or hoax authors.
   - guru - Saturday, 06/15/02 15:16:01 GMT

Coatings Shane, I am not a big proponent of powder coatings as I have no experiance with them. I KNOW the three coat system I recommend over and over works at least as well as what the powder coaters claim.

Ask the powder coat guy for examples of his exterior work that are ten years old or more and go LOOK at them. Ask the owner if they have been repainted.

Making a hard layer of plastic thicker may make it more likely to chip in larger pieces. . . But according to some of the powder coating lit thicker is better. Then again, they claim the finish "does not chip". I consider that a rather childish claim. . .

High production finishers send out samples for salt spray testing (ASTM B117). Testing times vary according to the end application. Auto parts are tested for 500 hr and electrocoat tested for 1,000 hr. These are accelerated tests that assume an unbroken finish. I do not know what the standard is for exterior work.

Bob Utech of Powder Visions says in a finishing dot com forum, "For a few bucks more per pound of powder, you can
change the powder chemistry to super durable. This is top flight for any outdoor usage of the type. Powder's performance hinges in the substrates pretreatment."

If you and your customer are really concerned about longevity and low maintenance then powder coat over hot dip galvanizing is the best finish according to many. However, care must be taken in the post cleaning treatment of the galvanizing. The galvanizer should be told the product is to be powder coated.

My research into powder coating indicates that the primary advantage is that it does away with solvents (an environmental concern) and that it is more economical than paint in many applications.

However, surface cleanliness is still the number one problem. Powder coatings will fail for the same reasons as paint, embeded weld flux, scale and porosity leading the list. Assemblies with ANY welding of any type using flux must be carefully cleaned. Not only are fluxes hydroscopic, the finish does not properly adhear to it. Many chemical cleaning processes do not work on borate fluxes so sandblasting is required. Porosity around welds or overheated steel can harbor moisture or oils either of which will cause paint OR powder coating to fail.

There is ZINC paint and then there are zinc rich primers. . You have to look closely at the ingrediants. Percent by weight is often used to fool you into thinking that there is a lot more zinc than there really is. Zinc is 7 times more dense than the binder. So 90% by weight may mean less than 30% by volume. . . Zinc compounds ARE NOT the same as zinc. It is the zinc (like in galvanizing) that provides galvanic rust protection, especialy if the finish is broken.

We had one person note that their powder finisher had a "marine" finish that included a zinc undercoat. This was a two coat process.

Don't ask your finisher to do something that is not a tested
method. You are asking for trouble.

As always, everything depends on how much you (or your customer) are willing to spend.

   - guru - Saturday, 06/15/02 16:33:01 GMT

Guru, an update on heating large stock in a Whisper Baby. Recall that I wanted to forge some anvil tools from 4130. Had 2 pieces 1-1/2 x 1-1/2 x 3". The Whisper Baby heated it to bright yellow in about 1/2 hr from a cold forge! Alas, this old man doesn't have the arm to forge something that heavy. Smote it a mighty blow and never made a mark! I decided to take your advice and buy some.
   Quench Crack - Saturday, 06/15/02 23:24:49 GMT

Will a gas barbeque. Work for a gas forge, if it has enough Btu's?
I have bin pondering this for some time now and I think it will.
But I thought I should ask someone who would Know.
And is there any thing that I would need to do to it to make it work for general use?
Thank you for your time. Jayden.
   Jayden - Sunday, 06/16/02 01:41:48 GMT

Jayden, Sorry, no it won't work. A barbeque only needs to produce about 400°F to 500°F to sear a steak and much less to cook meat. Things put directly in the flame will get hotter but not enough. A gas forge runs 2,000 to 2,500°F. The difference is the refractory enclosure that is balanced in volume to the output of the burner (BTU to volume). To get maximum heat forges run slightly pressurized (still vented but with a little back pressure). The increased pressure raises the flame temperature considerably.

The combination of refractory to hold in the heat, the burner balanced to the enclosed volume, and the increased flame temperature are what makes a gas forge.
   - guru - Sunday, 06/16/02 03:30:17 GMT

Whisper Baby: I've never heated anything that size in mine and didn't think it would do it in a reasonable length of time.

Note however that it is common to get a surface heat with a gas forge in a short time while the interior of the piece is below forging temperature. The result it a piece that LOOKS forgable but is not. . . But in any case a 1.5" square is a BIG piece of steel to hand forge. Its like forging SIX 1/2" square pieces at once. . . Smiths do it using sledges or hand hammers much heavier than most of us can swing. I have an eight pounder (3629g) that does a fair job on heavy stock but you don't want to swing it much. It also requires a large anvil. Something 150 pounds or more.
   - guru - Sunday, 06/16/02 03:49:32 GMT

I would Just like to thank all who had answers for me. on the bbq. question.
   Jayden - Sunday, 06/16/02 07:08:42 GMT

Guru & everyone that helped:
Well, The treadle hammer is completed. Thank you very much. It works great. This will save my arms & hands and I will now beable to continue in Blacksmithing. I will be adding some extra weight. I decided to design something similar to a scale weight. Weight can be added and or subtracted. This will be secured to the head. A Pole secured in the head with slide with a keeper bolt threaded in the washer.
   Gerry W. Jones - Sunday, 06/16/02 11:38:08 GMT

Guru/Shane, I have found a great way to treat outdoor ironwork. A company that is (fortunately) about a mile from my shop, E.D.Coats, Oakland, Ca.. They are a zinc electroplating company. The advantages over galvanizing are many but primarily it is because it is only a 4 mil coating which allows any forging and details to show. The electroplating can then be "patinaed" with chemicals from another company in los Angeles, SSS Chemical. The chemical treatment we just put on a railing was almost instantaneous and looked EXACTLY like rust which was then clear coated with a water based laquer. This is an inexpensive, fast, easy, long lasting solution. If you can give a procedure I can post some pictures. Tim
   Tim Cisneros - Sunday, 06/16/02 13:36:50 GMT

I'm looking for a tomahawk eye drift, any ideas where to find one?
   muskettforge - Sunday, 06/16/02 14:33:37 GMT

most folks make their own.

   Ralph - Sunday, 06/16/02 14:40:24 GMT

I have made a couple but I have been told that Centaur used to carry them.
   muskettforge - Sunday, 06/16/02 14:50:16 GMT

Shane-- just some more info on your slitting problems. Using a power hammer or by hammer in hand, the techniques are the same. Mark your slit on both sides with two center punch marks and\or a cold chiseled line, and slit half way thru each side.. watch how the cut is going, and rotate your bar and or the slit chisel, to keep it going in straight. If you go too deep from one side, this is a prime way to distort the slit. If your chisel gets stuck in the cut, before this happens, start your slit, then quickly remove the tool and put a bit of coal dust in the slit, then finish the slit to half the thickness of material and this will keep the chisel from sticking.

H13 is a good steel for this work, but don't let it bottom out on cold metal of any sort, just keep it in the hot stuff, one missplaced blow on a cutting plate, and h13 gets dull, no matter how well its hardened and tempered. For slits near the end of bars, the end portion has less mass than anywhere else, so leave extra material there -- a couple of inches or so depending on thickness of material, then cut it off after the hole is slit. This way the frogs eyes stay symmetrical on the sides. I was unsure as to whether you were drifting these round or not after the slit for passthru's, but if so, then let me recommend Francis Whitaker's book, The Blacksmiths Cookbook there is a great table in there for proper width of chisel for final round hole diameter. Sorry, but I have that in the shop at the moment, and hehe its not in metric.

Oh yes, if you slit in one heat and get tool deformation, thats just a pretty good idea, that you should take two heats. Sorry im not good with metric, but 33mm is around 1-1/4" I believe. You should be able to slit this in one or two heats but again do it from two sides, and quench the H13 tool between applications, or use two tools. Sorry but ya lost me in the metrics as to tool shape, so generally, a slitting tool is very thin, and should keep this thinness lengthwise, at least to the deapth of the cut you are making. The idea being that you don't want the force to be used to move material laterally, but just to do an inboard shear, so fatboy tools mean more effort, and BTW more distortion of the bar in question. Hope this helps. . .
   anvil - Sunday, 06/16/02 15:02:33 GMT

Metric: Anvil, Our "Tool Kit" button to the left pops up a simple little conversions calculator for common metic units. 33mm is indeed a little over 1-1/4". Thanks for the detailed post.

Coal Dust is used to cool and lubricate punches and chisles when doing hot work. Heavy grease can also be used. I'm a big proponent of Never-Seize and many recommend it as a punch lubricant, but I have not tried it.

Slitting Length: We have a formulas in the iForge article #64 Punching II and slitting for determining the length of slit for square and round holes.

8 pound Sledge: The 150 pound anvil size I gave above was a minimum for short handled single hand sledge use. Anvils used with sledges must be as large as possible and set on a secure stand.
   - guru - Sunday, 06/16/02 16:58:15 GMT

Tomahawk eye drift:

Many smiths do make their own, but Norm Wendell's Iron Mountain sells cast ductile iron ones that work better than any of my own hand-mades. They don't do internet, you have to call or write. Unfortunately, I seem to have lost my price list, so I can't give you the number or address! The drifts are about $20, though.
   Alan-L - Sunday, 06/16/02 18:12:13 GMT

guru-- hey pretty cool tool that tool kit is.. thanks.. also i believe using coal dust with punches and slits creats a bit of a compressed gas below the working end of the punch and this is what helps the tool to not stick...
   anvil - Sunday, 06/16/02 20:03:43 GMT

After spending an hour or so looking, finally found it.

Norman Wendell
180 Marks Avenue
Lancaster, OH 43130

(740) 654-2040

They have a whole range of neat stuff, all cast from ductile, and all relatively cheap. The best part is they ship first, bill later, and don't take credit cards. They should really pay me for all the advertising I've done for them!
   Alan-L - Sunday, 06/16/02 20:10:03 GMT

guru- read the iforge slitting\punching demos. pretty cool. Francis' formula for slit chisel length is a bit less complex than yours, for round stock, he uses diameter + 40%, and it works out right on the money.. also might suggest upsetting the slit before using a drift. this assures that the thin edges of the frogs eye don't lose any thickness,, ie a split in a 1\2" bar will give 1\4" sides. if you drift first, they will invarible thin out. just a nice detail to be aware of. Btw i was at Ripley too,,, sheesh what a long time ago.. had a lil "S" hook on display in the gallery..:)
   anvil - Sunday, 06/16/02 20:44:17 GMT

Thanks for the info on the tomahawk drift.
   muskettforge - Monday, 06/17/02 00:53:37 GMT

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