This Setting Tool for use with post rivets or tubular rivets (not for use with brass two-part rapid rivets).
Punch a hole in the leather, put the post rivet through, put the pin end of this tool in the throat of the rivet, give it a good whack with the mallet, and the
end of the rivet splits into six flower petal sort of things, holds the leather quite well. These setting tools are hardened steel and have a long life span -
to make them last you MUST use a nylon or rawhide mallet - NEVER USE A STEEL HAMMER - and a cutting board/pounding pad.