Thursday, November 8, 2012

Creating a frustum of a cone with hand tools and more

Say what?  The project I made this week is pretty basic, another hand tool skill building exercise from the Paul Sellers course (which I will shortly be doing a review of here), so I amused myself by making it sound technical and sophisticated.  If you have forgotten your high school geometry, a frustum is basically a cone with the tip cut off parallel to the base.  My project is a stool with cone-shaped legs:

Turns out that his method is straightforward, it isn't as hard as it sounds and I really enjoyed it.  A plane and a spokeshave are the tools used.  Actually, the difficult part was creating a cylinder on the top to fit into the 1" holes bored in the seat.  I was making very slow progress when a light went off.  I remembered that a 1" dowel precisely fit the inside of my gouge.  It worked very well for shaping the round tenons, though I suppose this is cheating.  I am liking this gouge more all the time.

The holes for the legs were bored more or less by eye and I surprised myself by getting the splayed bottoms of the legs to within +/- 3/16".  So as not to push my luck, I think I will go with a variant of the Curtis Buchanan approach in the future.  He uses a square and a bevel gauge sitting on the seat blank to drill the holes for the legs of his Windsor chairs.  If you haven't watched this series, I highly recommend it.  He is very skilled and has a pleasant, effective delivery.

Though the stool project is a simple one, I found it immensely satisfying.  I actually like and have a use for the stool but, far more important, I came away with some significantly improved hand tool skills that I can bring to more challenging projects.  I find that I am less willing to take chances and try new things when I am working with expensive wood on a major project in which I have invested countless hours.  I have a big pile of this alder which I paid almost nothing for, it's no big deal if I have to start over and it's fun to finish a project in a day sometimes.

Finally, while I was working on this project I started thinking about three-legged vs. four-legged stools.  Three-legged stools have a distinct advantage when used on uneven surfaces but it seems to me that they require a bit more in the way of "active" sitting: you add stability with your legs.  Deciding to do some research, I came across an article in Fine Woodworking magazine by Graham Blackburn about the history of stools.  Three-legged stools like the one I made were early and were supplanted by four-legged joint stools.  Turners made the early stools but the four-legged stools used mortise and tenon joinery, which only joiners were licensed to make.  Reminds me of some of the patent litigation I have been reading about in the newspaper lately.  Plus ca change ...

You can see an excerpt from the DVD about making the stool here.

On to joinery.  As readers of this blog know, I made a major push on improving my dovetailing technique recently with some success.  Nevertheless, I found several techniques in the Sellers' DVDs that represent distinct improvements.  I'm getting closer to having my joints fit off the saw, although it's obviously easier in alder than cherry because the fibers can be compressed somewhat.

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