easy way to shorten a screw or a bolt without having to re-die the threads...
i never have the right length screws or bolts and am always needing to shorten them. here is a
trick. place the length to be cut off in the vise so you don't mangle the threads of the piece you
want. Make sure you have placed a wingnut or nut of some description on the end you wish to
keep. Later you wind this off to clean up the threads so you don't need to re-die the screwthread.
Step 1: Place Nut or Bolt on Threads.
a wing nut is good, any nut will do. this will effectively by your die for cleaning up the threads.
Step 2: Mark Cut and Place in Vise.
i have marked the screw (green marker) with the cut off length and am holding it in the vise on the section of thread that is to be discarded.
Step 3: Hack Saw Off.
hack saw is fast and effective for small diameter screws and bolts. you might need a cut-off wheel
or dremel for hard steels and larger diameters.
When you are finished wind the nut off and in that process the thread will be fixed by the nut as it
comes off. It wont be perfect but it will prevent cross threading and make starting the thread a lot