An angle grinder is the best tool to use for trimming down exposed bolt ends. Here's how to do it.
To do this, you'll need a bench vice and an angle grinder with a metal cut-off wheel. Use a Sharpie pen to mark where you want to cut and use the vice to secure the head of the bolt. With the angle grinder on, approach the bolt at a flat angle and cut right through.
Use a bench grinder or abrasive pad to clean up the end of the bolt and use a wrench to get the nut started and rethreaded onto the bolt.
After cutting the bolt, wait a few seconds before touching it as it will be extremely hot.
Always wear safety glasses when using an angle grinder and take note of where the guard on the grinder is facing to catch the sparks. Be aware of anything flammable on your workbench or in the immediate vicinity and remove them to prevent fires.
Cutting threaded bolts with an angle grinder [FERM TOOLBOX TV (YouTube)]