The Hammer Filing Jig provides a flat, smooth surface from which to control the filing of upright or grand hammers with a drum sander. It installs on the table of a drill press with the turn of the magnet's knob if the table is ferrous metal or through two screw holes onto a block of material that is then clamped to the table. Fully tapered hammers will not work, but hammers with flat sides extending partway down the molding are held by weight of thumb and arm applied at the moldings tip. A light pressure toward the drum is easily controlled to produce a smooth and square surface, ideal for good tone when strings are fit to it. File from the more visible side to the other side in one smooth motion from shoulder to crown (lighten up as you cross the crown) to shoulder. Start in the bass where there is plenty of felt and adjust direction of filing in response to grain of felt. Occasionally, the traditional filing to the crown from each shoulder and then clearing the tuft is needed. The other hand guides either the hammer or, if hammer is glued to a shank, the shank. The Squaring/Filing/Voicing Block serves as a hammer support (their tails stand on the SFV Block) approximately at strike for hand and gang filing when a Squaring Platform is unavailable. With a Hammer Square, it serves as the horizontal base to square hammers to vertical and as its name suggests, it can also support hammers for needle style voicing. .