Friday, September 5, 2014

Prototyping and design

The chairs I am working on are not traditional Windsors--they're what you might call Modernist Windsors, with clean lines and most of the ornament stripped out. There are a number of chairs in this style that I like, such as Nakashima's New Chair, Moser's Eastward chair, and Curtis Buchanan's Patra's chair (as well as his and Peter Galbert's more traditional birdcage chairs). But there's no blueprint or scaled drawings to follow, so I'm making it up as I go along. This can get a little overwhelming, so I decided to do some prototyping. I got a couple cheap Southern yellow pine boards from the Home Depot and made a practice seat (my real seats will be made of elm).

The traditional tool for roughing out a seat is an adze. I don't have one, and they're not cheap. I do, however, have this:

It's a Lancelot "chainsaw" carving attachment for a 4.5" angle grinder. I bought it 7 or 8 years ago and never used it. I think it was only about 30 bucks. Boy, did it come in handy. I was able to rough out my first seat in about 15 minutes. Like a router, it tends to self-feed if you move it in the wrong direction, though not nearly as bad as a router does. But once you figure out the right direction, it's extremely controllable. Of course, it leaves a very rough surface.

But another half hour with the travisher and it was looking pretty good for a first try. And most important, I know what I need to do to make the first real seat a lot better than this.

The real seats will get scraped and probably sanded, but this was good enough for a prototype.

Next, I bored and reamed the seat holes. I'm using 14° for both the rake and splay. I got these numbers from a drawing of a birdcage chair in John Kassay's wonderful book, The Book of American Windsor Furniture, which has dozens of elaborate, scaled drawings. Using the tables in Drew Langsner's The Chairmaker's Workshop, I converted these angles to a 45° sighting angle and 20° resultant angle.

I forgot to take a picture of the reamer in use (the one I showed in this post), but suffice it to say that it works great. It cuts slowly, but that's an advantage, because it gives you multiple chances to dial in the right angles. My first hole was a little wonky--not surprising since I'd never done this before--but the other three were pretty much dead on.

This looks enough like the bottom half of a chair that I think I can tackle the real thing. But first, I'm going to try mocking up at least the outer spindles and the crest rail.


  1. Hi Steve, that looks real nice. Your method of roughing out the seat should work plenty well. I recently made my first chair and used an elm seat blank. I did have an old adze, and the surface it left wasn't nearly as smooth as your roughing tool. :o) A little work with a travisher and it is just fine.

  2. Thanks very much Brian. I'm glad someone else is using Elm!

  3. Another coincidence Steve, we've been making adze blades at the college the last two days. They'll be used on Galbert type heads and handles for a bowl carving class with Curtis Buchanan next week. We've made a variety of bade widths and cup diameters to see what's going to work best.
    Cheers, Bill

    1. Bill, if you have any spare adze blades that you'd be willing to sell, let me know. I love the design of Peter's adze. But you've seen how many tools I've made for this project; at some point, you just have to go with quick & dirty.