# Motorizing a rotary shear



## AGCB97 (Apr 12, 2022)

When I cleaned out a large machine shop for a friend a few years ago, I found this shear.








It worked well and was in good shape with all the parts present. There are quite a few on EBAY, most for over $300. Many of those are missing parts. These seem to be from the early 1900s, teens or 20s.

The problem was that when cutting thicker sheet that needed a little more finesse to control
the cut, one hand on each of the sheet and crank was not good enough.

So I got to thinking that some sort of motor drive conversion should really help. I went looking in the motor stash and found a 3 phase ¼ HP 50:1 gear motor. The output RPM was stated at 35. That's about 1 turn of the crank every 2 seconds. Seemed about right when I turned my hand in a cranking motion while trying to count seconds in my head.  

Not only that but both shafts were 3/4”.

I made a quick coupler and married the 2 together with some bar stock. Put them both on a plywood base for stability and put on a temporary cord to plug into my mill VFD. Also got to use the quick 45 attachment for the Johnson band saw but had to use a couple Vise Grips because the stock was very short.












It works great and with the VFD it has even slower speed control and reverse too.

Still have to complete the wiring (add a box to the motor) and I want to try making an adjustable pivot for cutting circles.

Thanks for looking.
Aaron


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## pontiac428 (Apr 12, 2022)

That's super heavy duty!  Mine works the same, but is for smaller stuff.  These rotary shear tools are reliable and last a very long time without service or replacement.  More the exception than the rule, don't you think?


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## AGCB97 (Apr 12, 2022)

I think


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## brino (Apr 12, 2022)

Very clever and thanks for sharing!

It's good that it's bolted down it looks a little top heavy.

Brian


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