Cutting a threaded screw shorter

The aileron inboard attach bracket calls for trimming the MS24694-S67 screw on the threaded side so it fits into the cut out area of the top nose skin and rib. What is the best way to trim this without messing up the threads?

Use a nut to restore threads

There are a couple ways that work for me. The goal is to have a nut or equivalent on the screw or bolt proximal to the cut. I clamp the bolt in a vice and use a hacksaw to carefully cut the bolt then back the nut off restoring the threads. Dress the cut edge of the bolt on the 3M wheel and you are good to go. Small machine screws can be cut with the screw cutter found as part of many crimpers. Remember the threaded part must be on the "good" part of the screw.

Chuck

I do it the same way as Skyflier.

Run a nut further in that where it needs to be cut, make the cut (I like a dremel with a cut off wheel personally) and then take the nut back off. The nut acts like a poor mans die.

Hold the the bolt&nut with visegrips and let the beltsander do the shortening and deburring in one setup.

I have to shorten screws pretty often at work, I grind them to length and then hit the end on the cut and polish wheel, it cleans and removes any damaged sections of thread. The "screw the nut on, grind the bolt/ screw, remove nut" methods ended up taking to long.

Before you do this, see if you even have an interference issue. I didn't.

Beat Way to cut a Screw

You asked what is the best way? I guess it depends on what tools you have. Luckily I have a lathe and this is what I use to cut excess threads. Like the other posters, I thread a nut (plain, non locking) onto the threads first, then grip the bolt head and nut in the three jaw chuck. Use the parting tool to cut off the excess thread, then use the lathe file to chamfer the end of the threads at 30 degree angle. Threads have a 60 degree included angle, so this takes the wire end off the last thread. Remove from the chuck, unthread the nut and if you have done it right, there will be no resistance in removing the nut, so then you can thread on a self locking nut without damaging the self locking part.

I would think the "best way" is just buy the correct length MS24694 screw Vans only sell a small selection and cutting down is an option. But if you are making an order elsewhere, for ~$0.10 it could be yours

Link

Most wire crimping pliers have screw cutters of different sizes built into them,
Screw the offending screw into the threaded side to the length you want and squeeze.