Pattern-sanding Curved Parts

This is straight from André Roubo’s “L’Art Du Menuisier” in the section on oscillating spindle sanders. True, the spindle sander shown in plate 322 is treadle-powered, and the menuisiers shown are wearing frilly shirts and tights, but other than that, it’s stone-cold André.

When I make arm bows for chairs, I struggle with getting the inside and outside surfaces parallel and looking good. I can rasp and shave them until I’m hoarse, but I still can’t get them perfect. And if the curves look lumpy or misshapen, it shows. (Some errors in chairmaking are easy to hide. This error is not.)

With these arm bows, I bent them around a form and clamped them. The inside curve is fairly smooth, but the outside curve has some divots from my clamps.

Here’s what I do: Take a block of oak and cut a 45° on one end, leaving a 1/8″-wide flat. Clamp that to the table of our shop’s spindle sander so the distance between the block and the drum is a shade less than current width of the bow.

Then I run the arm bow through the rig: The smooth inside edge rides on the block, and the drum reproduces that shape and width on the outside curve. Two passes and I’m done.

A couple details for commenters who are raising their hands right now: Yes, Epstein, you could just use a flat fence instead of a single-point stop, but you have to be real cautious about where the arm bow touches the fence. If its position shifts around on your fence, you are a goner.

And yes, J.J., a better fence would probably be a double-point fence to create a stable three-point area of contact between the fence (two points) and the drum (one point). So try that if you like.

André would approve.

— Christopher Schwarz

Other Chairmaking Resources
• “Welsh Stick Chairs” by the late and great John Brown is back in print. Get it now. Amazon.com has it here.

• The other great chairmaking resource “The Chairmaker’s Workshop” by Drew Langsner is also back in print. You can order it from Drew direct.

• “American Windsor Furniture: Specialized Forms” by Nancy Goyne Evans is on sale in our shop. These books are a gold mine for people who love chairs. They are expensive now, but you ain’t seen nothing yet. Wait until they go out of print! You have been warned.