Cutting tiny machine screws to length

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Chucketn

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I am assembling a team built beam engine on which all fasteners are 2-56. I purchased 100 2-56 x 3/4”, stainless steel hex head screws for this model.
I have made a couple jigs from 1/2” mild steel hex to accomplish this on my lathe. One jig is 1/4” and one is 1/2”. I drilled and tapped each jig for the 2-56 screws, and have cut several to the size required for various components. I am having trouble with the current process. I have to really tighten the screws in the jig or they catch on the parting tool and begin to screw themselves back out of the jig.
How do you cut longer screws to length? Do you have a better way to do this without buggering the threads?
BTW, I made a nut driver type tool from a socket head cap screw, piece of brass tubing and a home made wood handle for these screws that seems to do the job, although the brass hex nuts I have are bigger than the hex screw heads.

Chuck
 
Double-nut the fixture.


2-56? Sheesh, with my fingers, I would NEED a box of 100 to increase my odds of picking one up, not dropping it and actually getting it in the hole. Good luck.


Ray


chucketn said:
I am assembling a team built beam engine on which all fasteners are 2-56. I purchased 100 2-56 x 3/4”, stainless steel hex head screws for this model.
I have made a couple jigs from 1/2” mild steel hex to accomplish this on my lathe. One jig is 1/4” and one is 1/2”. I drilled and tapped each jig for the 2-56 screws, and have cut several to the size required for various components. I am having trouble with the current process. I have to really tighten the screws in the jig or they catch on the parting tool and begin to screw themselves back out of the jig.
How do you cut longer screws to length? Do you have a better way to do this without buggering the threads?
BTW, I made a nut driver type tool from a socket head cap screw, piece of brass tubing and a home made wood handle for these screws that seems to do the job, although the brass hex nuts I have are bigger than the hex screw heads.

Chuck
Click to expand...
 
Turn your parting tool upside down or mount it on the far side, and run the lathe in reverse. This will cause the screws to tighten rather than loosen.

But, I generally just use a Dremel with an abrasive cut off wheel.

Ken
 
KMoffett said:
Turn your parting tool upside down or mount it on the far side, and run the lathe in reverse. This will cause the screws to tighten rather than loosen.
But, I generally just use a Dremel with an abrasive cut off wheel.
Click to expand...

+1 on the Dremel. Put a nut or two on the screw and then cut to length.
 
Seems like you could continue to use your little jigs, but skip the parting off in the lathe. I think I'd simply snip the end off with a diagonal cutter and file off the cut end neatly while it spins in the lathe. OR, not even use the lathe, but snip the end, and grind off the bit freehand on bench grinder. Should go pretty quickly.

Actually, I have five different setups outlined on my Web site that I've used for shortening or otherwise machining the ends of screws:

The simplest - for teeny ones, especially setscrews: http://www.frets.com/HomeShopTech/TechGen/ShortenScrew/shortenscrew.html

Stepped Screw Plate: http://www.frets.com/HomeShopTech/Tooling/ScrewPlate/screwplate.html

Special holders for cap screws: http://www.frets.com/HomeShopTech/Tooling/CapScrewHolder/capscrewholder.html

Small chuck "accessory" for jaws: http://www.frets.com/HomeShopTech/Tooling/ScrewShortenChuck/screwshortenchuck.html

Modfied Chuck for close work: http://www.frets.com/HomeShopTech/Projects/CloseChuck/closechuck.html
 
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I recall one of the "Knifemaking tuesday" videos, he shortens a bunch of screws by driving them into a screw plate from the bottom, then facing them off with a shell mill. It does involve making a plate with a bunch of 2-56 holes in it. Course frank is probably right. Make a little holder, and free hand them on the bench grinder, bet you could go through 100 pretty quick.
 
Thanks everyone for the great suggestions.
I don't have to shorten all 100 screws, just enough for the build at hand, maybe 16 pairs, most of which seem to be different lengths. I work with 2-56 up to 10-32. Looks like a double or quadruple row screw plate is in my future. I'll get working in it as soon as the weathre warms a bit.

Chuck
 
On most wire terminal crimping tools there is a place to screw in a screw such as that and just shear it off when you unscrew it out of the tool it straightens the threads right up.. Ray
 
Ray, the smallest I have seen is only 6-32. I'm working with 2-56. I have those type of crimping tools and a T-Strip tool, but they won't work in this case. I would if they could, LOL!

Chuck
 
For a few screws, what I do is to double nut them to the desired length, clamp in a bench vise, then file off the excess. The threads are mostly protected, and anything hanging off the end of the screw is re-formed or broken off when you remove the nuts.

More than a small number and it may save time to make a jig.

Walt
 
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