When preparing an object to be filed, it should be fixed in a vice so that it cannot move around.
Filing is a two-handed job, leaving a DIYer short of a way to hold the workpiece steady if a vice is not used.
A filing block is a protective piece of material that prevents damage to the object you’re filing by keeping it out of contact with the vice’s hard jaws.
Filing blocks are usually made from wood or soft metal. You can use any suitable item that’s lying around in your workshop!
It’s possible to use thick cloth in place of a file block, although this is much less effective than wood.