Side clamps start with raw block of metal too, then squared. Fast forward to holes cut, threaded and slits cut.

Side-clamps raw material Side-clamps with holes drilled

Side-clamps cleaned and blued.

After cleaning and quality time with files to remove sharp edges. Bluing applied to make the new tools 'look professional' and prevent rust.

Side-clamps in use to hole label jig

A side clamp in place against the label jig. The recessed cap screw on the top draws the T-nut up tight keeping the side clamp for sliding. (Part of the T-nuts can be seen in the red T-slots.) The two set screws on the side, press against flexible side clamping the part being held.

With two side clamps, the part/material being worked on is held in place. 

With the side clamps completed, back to making the jig.

Front view of jig being held by side clamps