How Do You Cut Screws To The Proper Length?

[mikey]

There are times when I need a screw of an accurate length but holding a small screw can be tough so I came up with a little tool that is very handy.



I can hold up to a #10 screw with just about any head - SHCS, button head, pan head, etc - very solidly for hand grinding or I can chuck it in a lathe and cut the screw to a precise length.

The brass heads have either a flat surface inside the bore or a 82 degree chamfer that will fit a #10 screw. For smaller screws I use a washer sized to fit a #6 or #8 screw to center the screw in the head. When the head is threaded on to the shank of either the hand tool or the shorter bar that chucks into the lathe the nose of the tool pushes the screw solidly into contact with the inside of the head and the screw is held very solidly.



For storage, one of the heads remains on the nose of the hand tool and the other, with washers inside, simply screws onto a retaining screw in the handle.



This tool works very well and holds the screw very solidly with just hand pressure on the head. Anything that distances your hand from a grinding wheel or belt is a good thing, right?

 

[Cadillac STS]

If I were to find the need to cut screws really often I would find myself a good source for screws and just buy them the length I wanted.

 

[RandyM]

I just cut the bolt or screw to the length needed--then I hold the bolt to about a 45 degree angle to the grinder or sander and rotate the bolt once around---it works every time----putting a nut on first and then backing it off works ok--but still may have a sharp end on the screw that still needs to be ground smooth-----that's why I just grind them to begin with since it is faster---you don't have to find a nut--- and always works----Dave

Best method there is, fast, cheap, and works perfectly every time.

 

[Skarven]

For small screws, I use the wiring tool with screw cutter and put a nut on short of the cutter, but for 4-5mm and up I allways put 2 or (if room) 3 nuts on it and put it in the lathe 3-jaw. It is very easy to get the right shortening everytime if you have a DRO (Probably without a DRO too). When the 2 or 3 nuts are removed, there is normally no need to clean up the thread. It is also easy to put a nice chamfer on in the lathe.
If you want rounded screw ends, use a radius milling cutter as a turning tool.

Kai

 

[shorton]

There's an aircraft parts company Aircraft Spruce IIRC that sells a little bolt shear that I thought looked nice. Found it, here it is:

http://www.aircraftspruce.com/catalog/topages/screwboltshear.php?clickkey=21679

Pricey but looks nice...

I've got a spindle mount Jacobs chuck that for my SB9 that I've been using for #8 and #10's with my robotics kids. But I haven't mastered parting on those yet and managed to crash the jaws once.

 

[barrydc1]

If I want them precise and they are long enough, I put them through a 5C collet on the lathe and trim them down to the proper length. If they are short, I put a nut on them (or two if they are long enough) they are screwed tight to the nut or the two nuts are tightened so the bolt or screw won't rotate and then chucked on their flats in my 6-jaw on the lathe and faced to proper length.

 

[Rick Leslie]

I have a scrap piece of 3/16" plate that I drill and tap for the screw in question. I thread it in to the proper length and lock it with a nut. Then give it a quick tour of the bench grinder. When I back it out of the plate it cleans the threads.

 

[rwm]

I'm glad I started this thread. Lots of great tools and ideas.
I am torn between building a bandsaw jig and building a small cutoff saw with an abrasive blade. I may do some experiments to help me decide. What would be a good motor for a dedicated unit? I was thinking one like this might be good:
http://www.harborfreight.com/120-volt-circular-saw-blade-sharpener-96687.html
I would need a real narrow kerf cutting blade. 2" would be ideal.

R

 

[Bill C.]

If length is critical, I usually put a nut on to the screw where I'm going to cut it. Sometimes I'll put 2 nuts on and lock them together. Then I cut against the nut with a hacksaw or band saw. The nut served 2 purposes, to hold the length and to form the threads on the screw as you back off the nut. The nut does it for me.

I find double nutting works great for me. The nuts ensure there is no bad thread on the end. I cut the extra length off then grind a chamfer using a belt sander or coarse grinding wheel.

 

[Ranger]

Wow after all this I feel a little anal about how I shorten my machine screws and bolts
I take a piece of 5/8 mild cold rolled steel, mount it in the lathe, drill and tap a piece about
3/8 to 1/2 or other length as needed, screw in the bolt in question, determine what length I need
mount that in collett chuck turn to length by facing until correct, then bevel the end at 60 degree
and then save the cold rolled piece for later use, I have about 30 of them various lengths and
threads

:nuts::nuts: