The Pocket Mill Pro Loose Tenon Joinery System. No matter what your skill level, the Pocket Mill Pro will make high quality accurate mortises with a simple hand drill. Made out of anodized aluminum and stainless-steel components, the Pocket Mill Pro creates perfect mortises using our patent pending step down process. With each side-to-side pass, the jig automatically drops 0.050 thousandths of an inch, working its way through your material until you have that perfect mortise complete. The JessEm Pocket Mill Pro will take anyone’s woodworking skill to the next level.