Hi fellas. Shortening bolts. Easy right? Just get a hacksaw, hold it in the vice and saw away. Although sometimes the length is critical, or you have a cheesehead that won't stay put in the vice, or you are trying to cut through a hard material like stainless and the blade is skipping across the threads and buggering them up.
You engineering types will know this, but for the more technically challenged or OCD types like myself, here's how I was taught to shorten bolts many years ago. Particularly handy if you need to shorten several to the same length.
First, select your patient.
Wind a die down the thread to the amount you want to remove
Hold the die in the vice - not too tight, but enough to nip up the die and hold the bolt tight
Keep the blade flat against the die as you cut, using it as your guide
Turn the die down a couple of threads and reposition it in the vice,again nipping it up to hold the bolt secure
Use a flat file to clean up the cut, hold it at 45 degrees to remove the burrs
Surgery completed!