Round tenons are notorious for coming loose over time. To build stronger chairs and benches, I compress tenons before gluing them in. Then, as the glue soaks in, they swell back to their former size, which makes them extremely tight in their mortises. I start by turning the tenons 1/64 in. oversize on the lathe. Then I put them into a simple jig, which works with any vise to compress the tenons evenly. Make the jig by drilling through a block of very hard wood, using the same bit you’re using for the mortises. Then bandsaw it down the middle. This makes the hole undersize when you rejoin the halves. To make the blocks easier to align in the vise, I put dovetailed sliders in them as shown, but those are optional. Position the tenon between the two halves of the block as you clamp it tightly in a vise. Then unclamp the tenon, turn it 90°, and reclamp. This will compress the tenon just enough for a nice fit, and glue will do the rest.

—ROGER LAFLEUR, Brookfield, Mass.

Illustrations by Dan Thornton
From Fine Woodworking issue #303