Get a Clean Taper on a Site-Built Threshold Without a Table Saw

The Problem

A threshold fitted into an old house is rarely a rectangle. The opening has settled, the floors on each side sit at different heights, and the piece has to taper along its length or across its width to meet both.

Cutting that taper on a table saw means a tapering jig, a long shallow angle, and a workpiece riding mostly on the jig rather than the fence. In white oak it also means burning, because the blade is in a long slow cut with the grain fighting it the whole way. The face comes off the saw needing real sanding to be presentable.

The Technique

A thickness planer already makes a perfectly flat cut parallel to its bed. Tilting the workpiece relative to that bed turns it into a tapering machine.

1. Mark the finished profile on the end of the blank so you can see the taper you're cutting to.
2. Cut blocks to hold the blank at the angle you want. The difference in block height across the length or width of the piece is the taper.
3. Screw the blocks to the underside of the blank — the face that ends up against the floor, where the holes don't show.
4. Run the whole assembly through the planer, blocks down on the bed. The cutterhead removes stock from the high side first.
5. Take light passes and check against your layout lines. Stop when the cut reaches the line.
6. Unscrew the sled.

The tapered face comes off the planer even enough to need only a light sanding.