Any tips for cutting some 1/4" threads without messing up the threads

[jb garage]

SO I bought some threaded pad inserts for some bar stools. Trouble is, the shafts are about 1/2" too long and won't allow the shaft to fully screw in and seat in the bar stool. I am about to cut off 12 off these things a little shorter. I was going to dremel them and them use a die to clean them up. But any tips on doing as little damage as possible to the threads appreciated. And yeah, I looked for shorter ones for about an hour. tia.

 

[The Cobbler]

I would thread a nut onto the fastener & then cut it, remove the nut & a bit of clean up you should be good

 

[Leaflessshadetree]

Thread a nut (or two), cut and file a chamfer. Then remove the nuts to clean up the threads.

 

[mcbane]

One last detail: tighten the double nuts so that you can cut against one nut. That way an unsteady hand doesn’t result in damage to threads.


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[PugetDude]

You can also thread a 1/4" die onto the studs before you cut them off, that way you know you'll get nice clean cut threads when you back it off after cutting. Similar to using a nut, but no chance of cross-threading.

 

[bwringer]

You can also thread a 1/4" die onto the studs before you cut them off, that way you know you'll get nice clean cut threads when you back it off after cutting. Similar to using a nut, but no chance of cross-threading.

This right here!

But a nut should work, too. Just run it back and forth a few times as you're removing it until it works smoothly. You're not building a space ship here...

Also, a thread file is a great way to clean up any stray burrs.

 

[rlitman]

I have a set of thread restorer dies. Better than a nut or a die for this, IF you really want to spend money on another tool (the proper GJ answer).

But I can't say I use any of the above techniques much. I usually just clamp the cut-off end in my vise and hacksaw off next to the jaws. Then grab the good side pointed up in my soft jaw vise and use a fine flat mill file to finish the end.
Step 1: file it flat across to smooth the cut
Step 2: hold your file pointing up at about a 30 degree angle and cut a chamfer around the circumference always filing towards the center (this requires turning it in the vise a couple of times).

The depth of the chamfer should be not much more than the depth of the thread, so it only takes a few seconds to do once you're good at it, and you get a factory good end.

Alternatively, use a grinder or better yet stationary belt sander rather than a file if that's not your thing.

So, why do I not recommend using a nut to fix the threads method? Because it leaves behind burrs. While spinning off the nut does align the burrs with the thread, all it takes is one little bump and the burrs move again, and now you've got something that will lead you to cross thread. Plus burrs are sharp.

 

[CraigStu]

Step 1: file it flat across to smooth the cut
Step 2: hold your file pointing up at about a 30 degree angle and cut a chamfer around the circumference always filing towards the center (this requires turning it in the vise a couple of times).

The depth of the chamfer should be not much more than the depth of the thread, so it only takes a few seconds to do once you're good at it, and you get a factory good end.

I do similar but usually on the grinder or belt sander. Use light pressure and go around the bolt twice. I find that as long as the motion is toward the center of the end of the bolt it leaves nice clean threads.

 

[Milton Shaw]

Use vice grips or gloves to hold it so you don’t grind your fingers. Ask me how I know.

 

[rlitman]

Use vice grips or gloves to hold it so you don’t grind your fingers. Ask me how I know.

Lol, yes to the vise grips if you’re using a sander or grinder. A short bolt also gets hot.

 

[jb garage]

Great ideas above. Thanks all. Love to buy new tools but as one poster pointed out, Im not building a space shuttle here lol. I will put my die on first and then double nut.

 

[kbs2244]

Cut the new treads before you cut it shorter using the 2 nut way.

 

[SGKent]

my grand dadwhose, father (my great granddad) was a black smith, taught me how to use a mill file to round the edge on the bolt end so the threads are clean. That is all you need when you cut a bolt off. Just file it at 90 degrees to clean the cut up and round the sharp edge to a round one and the nut will thread on fine with no need of a dye or nut. You can do it on a grinder too if you have a really fine cool grinding wheel. Takes about 4 to 5 seconds.

 

[wssix99]

Cut the new treads before you cut it shorter using the 2 nut way.

Do this and then, using any file, just file the tip of the last thread down to take off the sharp edge - then new nuts will go on and off just like virgin threads.

 

[SALIV8]

my grand dadwhose, father (my great granddad) was a black smith, taught me how to use a mill file to round the edge on the bolt end so the threads are clean. That is all you need when you cut a bolt off. Just file it at 90 degrees to clean the cut up and round the sharp edge to a round one and the nut will thread on fine with no need of a dye or nut. You can do it on a grinder too if you have a really fine cool grinding wheel. Takes about 4 to 5 seconds.

I will try this next time I can. Thanks.

 

[matt_i]

One can also Higbee the ends of the cutoff thread.

If you look at the helical thread crest there's a thin part that's somehow folded over as a burr. Align your file with that and file in the "wound" direction of the thread until you get down to the minor diameter. The thread start will now be blunted or on an incline, but it starts and self-cleans. Its hard to explain in words, its a thread you might have seen on a fire hose. One can google "higbee thread start" for more info, but its nice to have when you only have a file and have to restore the end of an external thread.

 

[californiaHank]

One can also Higbee the ends of the cutoff thread.

If you look at the helical thread crest there's a thin part that's somehow folded over as a burr. Align your file with that and file in the "wound" direction of the thread until you get down to the minor diameter. The thread start will now be blunted or on an incline, but it starts and self-cleans. Its hard to explain in words, its a thread you might have seen on a fire hose. One can google "higbee thread start" for more info, but its nice to have when you only have a file and have to restore the end of an external thread.

Nice little tidbit of (useful) information - thanks.