In this tutorial, I'm in the process of shaping a large flat faced lock into a round-faced. There is a LOT of material to come off the cock, in particular. It's also very hard to hold with my fingers and file effectively without ripping off an equal amount of flesh along with the metal.
So here's the plan:
Soft solder a block on the flat side of the workpiece. Then you can flip, turn, file your workpiece any which way, by clamping the block in the vise. I can bring extraordinary pressure to bear on the file with no damage to my fingers, yet I have exquisite control over the shape. No chatter, no tipping of the part while filing, and I can bring lots of pressure to bear in exactly the right spot.
When done, heat and wipe solder off.
This works for any odd shaped part you can't hold conventionally that will accept solder. Trigger guards, lockplates, etc.
