Di-Acro Shear

There is something slightly depressing about having a superb tool without having its complimentary partner, assuming it was ever made. After putting up with the frustrations of working with a Chinese 3 in 1 press brake/shear/roll for the last fifteen years, I finally reached the end of my patience and started looking for a reasonably priced Di-Acro 24" shear to match the 24" Di-Acro finger brake shown here. As luck would have it, I finally found one at a price I could afford from a sympathetic machinist club member at a yard sale that the club hosts each September.

As-found condition

This shear and its 3'x4' table were in fairly good condition, but it looked a bit down at the mouth sitting across from the restored finger brake, so I decided to take some time and refurbish it to match. A teardown of the shear showed its basic quality and motivated a burst of cleaning and painting. Interestingly enough, one aspect I discovered was that the blades are completely symmetrical, which is to say that they can be both rotated and flipped to present four new cutting edges throughout the life of each blade. Sharpening is then simply accomplished by placing the worn blade on a surface grinder and taking a few thousandths off one or both of the short dimensions. I had expected a rake angle on each edge that would reduce those possibilities to two edges, or, like my Chinese shear, offer only one edge because of asymmetrical bolt placement, but a check with a machinist's square and backlight revealed perfect symmetry.

The workbench and base were the first pieces to be tackled, and once those were completed it seemed wise to temporarily store the base right on top of the workbench while I was cleaning and repainting the other piece parts. (Okay, I'll admit there was a little bit of domestic pressure to get the disassembled mess out of the parking space for my wife's car...it's no fun digging the car out of the snow or scraping ice off the windshield anymore.) I had to allow for access to the bottom to re-attach and torque the two big 1"-14 nuts that retain the vertical bearing shafts to the base, so the photo shows some pieces of 1/2" threaded rod that I used to temporarily boost the entire assembly up the air until completion. Once the rest of the assembly was installed, I lifted the entire ~300 pound shear above the threaded rods with an engine hoist to remove them, and set the shear down in its final resting place on the bench.

Halfway through!

With painted parts hanging from convenient places around the shop (for some reason reminding me of our socks and underwear drying in a motel bathroom during a long trip,) the remaining work consisted of cleaning out the old threads in castings and ordering new hardware from McMaster-Carr. The old fasteners were still serviceable, but had obviously not been in an air conditioned space for a long time, if ever. Rather than trying to strip the rust from these and other parts and blacken them, it saved time to simply order new ones. The original hardware was unplated grade 2 for the most part, but I prefer a black oxide finish. It contrasts well with the new paint, and with a coat of LPS-3 will last for years. One thing I discovered about the factory exploded drawing and parts list is that it is incomplete, conveniently ignoring several bolts and other pieces of hardware. It would be prudent to label these as you disassemble your shear if you decide to do a similar refurbishment.

Details, details...

Luckily, I never did need to replace any unique factory parts, though I did pick up the silly little triangle that Di-Acro makes to help with angled pieces of sheet metal, just to make the machine complete. I may fabricate something with a little more heft to it as a replacement, now that I have a model. There is an adjustable back stop that is useful for repetitive shearing to the same dimension, but thinking back over the years I've done very little repetitive work like that, so I haven't pursued one of those with any diligence. The result is shown below, and it functions as well as it looks, shearing .090" 6061 aluminum like it was warm butter. It's absolutely terrific to work with a real shear once again!

Ready to use!

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