Shop Fabricated Tooling: Press Tooling

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Shop Fabricated Tooling:

Almost all press tooling is shop fabricated.
In production shops it starts with detailed engineering plans and either commercial diesets or with precision dieset components. The work is done using the best most precision methods available to the shop. Diesets can be built in small shops with only a few precision tools such as a small milling machine, a lathe and a surface grinder. But even this modest capability is beyond many shops.

The primitive dieset shown here was built with only a small 6" lathe and drill press. The parts were flame cut, hand ground and arc welded together. The die holder is a hand forged ring, hand filed and ground to fit.

The guide pins are 1" CRS set in drilled holes and welded from the bottom. They were aligned parallel by eye and using a simple wedge shaped wooden gauge to measure their parallelness. The guide bushings are babbit poured in place.

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Stock Clearance

Welded die & Stripper

Punch Holders

Detail Drawing

This dieset uses a 2.5" diameter commercial punch and die from Roper Whitney for blanking candle drip pans from 16ga steel plate. It took about a week to build in little more than a country blacksmith shop. It is used on a manual 20 ton hydraulic press. In one afternoon it produced hundreds of blanks and has not been used since.

The stripper plate is fixed in position and is used to support the stripper springs. It is held in place by four bolts and four spacers made of common 1/2" pipe. The stripper springs are recycled automotive valve springs held in place by standard die stripper or shoulder bolts. Like most diesets it could use more/heavier springs.

Precision: All these roughly hand made parts must in the end have good alignment. Blanking dies for sheet metal typicaly only have a few thousandths of an inch clearance. To align the punch and die the die in this dieset is left loose, then the punch lowered until the die can be carefully raised by hand to engage the punch. Then the punch is lowered until the die is resting in its seat and the punch is engaged full depth. Then the bolts holding the die or die shoe in place are tightened. If there is noticable clearance between the punch and die the die should be centered so that there is equal clearance all the way around the punch.

In use punch and die sets that have a little looseness tend to self center. As the material initialy deflects and flows into the die the punch follows. However, when there is no material being cut there is nothing to help align the punch and a portion of its edge can come down hard on the die chipping one or both. If you have a loose press or dieset it is best not to operate it without work.

Blanking with punch and dies is very common. However, the standard punches sold by Roper Whitney are all made for punching holes and have "shear" built into them. Shear is either a curved face or a split face with two sloping sides. This reduces punching effort on thin material but the slug is not usable as a blank. To remove the shear from this punch the shear was ground off by hand using a 7-1/2" angle grinder and constantly cooling the punch.

Punch Holders: These are not standard parts on presses but every press needs one or more. These two in the photo hold different types of punches. The detail drawing is for a holder to fit the #4 and #5 fly presses that accept a 3/4" shank. Make the shank 1" #6 and larger presses. The punch recieving hole can be sized to fit other punches or custom tooling.