A Jig is a temporary tool used on a material to bend or hold in place while something happens to it .. then the jig is removed. This is the jig that bent the conduit used in build the round boat
<a href="//commons.wikimedia.org/wiki/User:1sfoerster" title="User:1sfoerster">1sfoerster</a>
CC BY-SA 3.0
<span class="int-own-work" lang="en">Own work</span>