[Illustration: Fig. 66.]
This cut represents a form of clamp used in holding the plates against
each other when being riveted.
[Illustration: Fig. 67.]
Fig. 67 represents a peculiar form of bolt for screwing a patch to
a boiler. It is threaded into the boiler plate, the chamfer rests
against the patch and the square is for the application of the
wrench. After the bolt is well in place, the head can be cut off with
a cold chisel.