2009-04-19

Backing Up

Assembling the bottom half of a Windsor chair is generally called "legging up." So, I figure, assembling the back must be "backing up," right? I hadn't assembled a square backed chair before, so I had to figure out how to do it, with this one. Prepare to be bored (no pun intended): this is what I did.

Unlike most other windsor chairs, even other square backs (including many rodbacks), this chair's two joints at the sides are at a significantly different angle (but not quite "perpendicular") compared to the joints at the tops of the spindles. I decided this required assembling the rod and posts first, and treating it as a single unit when assembling the rest of the back. This turned out to work quite well.

I first tapered the post holes, and set the posts in place. Then I clamped the rod to the posts, in the correct orientation and at the right height. In this chair, the rod should be parallel to the floor. I set a bevel to the angle between the post and rod, and confirmed it was the same angle on the other side. I used that bevel to drill the angled holes in the posts.

After removing the clamped rod, I measured the distance between the top of the posts, so I could trim the rod tenons just far enough for the posts to be lined up properly. The posts can rotate on the rod to any angle, but I wasn't sure how this would work in practice. It turns out that the distance between the bottom ends of the posts changes significantly with very small rotations at the post-rod joint. I measured the distance between the posts at the seat of the chair to make sure the post-rod angles were also correct.

It's possible for the top and bottom post distances to be correct while the posts aren't in the same plane (the whole back is twisted), so I eyeballed it while dry fitting it into the seat. Once I aligned the posts and rod correctly and dry fit them into the seat, I marked the orientation of rods and posts so I could reproduce it quickly in the presence of glue. I then sawed kerfs in the rod for the wedges, applied glue to the rod and posts, assembled everything, and wedged the tenons.

While the rod and post joints dried, I installed the spindles in the seat ("crack!"). In cases where my spindles hole angles weren't quite right, I oriented spindles that weren't quite straight, to compensate. I marked the spindle hole locations in the rod, and bored the holes by eye, sighting down the spindles. This was the weak spot: I'm not enitirely happy with the results of these holes, but I don't have a better solution at the moment.

From here on out, it was pretty much the same as the other chair backs I've done. I dry fit the back, and marked the spindles at the bottom of the bow, to saw wedge kerfs to the proper depth. Then, I hurriedly applied plain old Elmer's white glue to all 9 holes and 9 tenons, and fiddled with things until it I got it all in one piece.

Finally, I applied glue to the wedges and hammered them into place. I'm unhappy with my wedges: they've been cracking fairly regularly. I think I should probably use something other than maple. I think we used oak on my previous chairs.

Anyway, I warned you it'd be boring; there weren't even any pictures. But I would've appreciated finding this blog post via google, a few weeks ago.

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