Oscillating Spindle Sander

Overview

An oscillating spindle sander smooths and shapes curved edges. An abrasive-covered drum stands up through a table; the workpiece is held against it and moved by hand to follow a contour. What sets this tool apart is that the drum does two things at once, it spins, and it slowly strokes up and down. That oscillation spreads wear over the whole height of the abrasive sleeve and stops the grit from cutting a ring or burn mark into one spot, giving a cleaner finish and longer sleeve life than a fixed drum sander.

This is a benchtop machine that accepts a set of drum diameters for tight or gentle curves. The Oscillating Spindle Sander is built on the Base, with the Induction Motor driving both the Spindle & Drum rotation and the Oscillation Drive. Work rides on the Worktable & Inserts with a throat plate matched to the fitted drum, and the Dust Port pulls sanding dust down and away.

How it works

The Induction Motor is an induction motor with a worm cut on its shaft. That worm turns the Oscillation Drive: a reduction gear pair brings the speed right down and turns an eccentric cam. The cam rides in a follower yoke on the spindle, so for every slow turn of the gear the spindle is lifted and lowered once, the oscillation. Meanwhile a belt or direct path spins the spindle itself fast, so the two motions combine.

The Spindle & Drum carries a tapered rubber drum. Tightening a nut squeezes the drum so it expands and grips the inside of a tubular abrasive sleeve, locking the sleeve on without slipping. The sleeve is the wear part; the user swaps it and the drum to change grit or diameter, and drops in the matching Worktable & Inserts throat plate so the table gap stays close around the drum.

In use, the operator switches on at the Switch Board, sets the workpiece flat on the table, and feeds the curved edge against the drum, moving it steadily so the sander does not dwell in one place. For a bevelled edge the table tilts on its trunnion. The combined spin-and-oscillate action removes stock evenly and leaves a scratch pattern that crosses itself rather than tracking a single line. Dust drawn through the Dust Port keeps the sleeve from loading up.