backing
Process for creating joints, the parallel projections running the length of the book that act as hinges between the spine and the boards.
backing hammer 
Tool used to flatten the back of signatures to give the spine a fan shape.
face 
Slightly rounded surface used to strike the back of the signature and push it against the backing boards.
claw 
The tapered end of the hammer, used to flatten the backs of signatures.
backing board 
Metal edge of the press; the back of the signature is placed along this edge and hammered to create joints.