I thought a little update on the bookcase project was in order. I need to get this completed soon to make way both for the coffee table project and to get the piece into the house in time for for my in-laws, who are due to visit next weekend. We have a few boxes of books waiting in the wings, and I’m holding things up with my dawdling. I’ve been putting in some steady time, just not full time as I’ve been doing a bunch of CAD and fiddling around with machinery for the past few days. This coming week I hope to put a more concentrated burst of work in on the piece.
At the conclusion of post 1 in this series, I had completed the 48 tenons on the shelves. Next up were the 96 saw kerfs for the wedges, as well as a small rebate on the end of the shelf:
The bottom shelf is a carcase piece which doubles as a shelf, and like the sides and top, is made of Canarywood. Besides the 4 through tenons on each end of that board, I decided to put sword-tip miters on, to give a nice transition between the horizontal and vertical carcase pieces at their front face meeting points. The housings for the sword tip miters I did entirely by chisel:
Next up were the connections between the top of the carcase and the sides. I considered lots of different possibilities as far as the joints were concerned, limited in some respects by the assembly direction already established by the through-tenoned shelves and the direction they must slide into place.
So, here’s what I laid out:
Sawing for Teens, season 13:
Now it’s time to chop out:
The Japanese call this joint pattern momo-gata (股形), which basically refers to having one’s knees apart, the thighs forming a vee to one another. Yes, a delicate way of saying crotch. I hadn’t cut this form of joint before, so I took the opportunity to play around with it in this piece.
This board is most of the way there now, sans clean-up:
When the scribing was complete (I used a razor blade, BTW), I cut out the tenons on both ends of that top board in much the same manner as I had done on the side boards. Then some paring and cleaning out was required. It was then ready for the test fit.
This is live coverage of the first fit, off of the chisel work:
I was happy with the fit, following as it did right after the cut out and given that it was the first time I had cut this form of joint. The fewer times one has to put together and take apart a joint to achieve the desired fit, the better. Can’t complain at all about how that went, except about the Canary wood which is prone to flaking, tastes gross if you get any dust in your mouth, and just plain smells skanky.
The other side nearly comes tight, however the upper miter is a little fat and is holding things up:
I like this pattern of joint, as it seems to combine the best of the finger joint and the dovetail. A little easier to cut and fit than dovetails, yet looking much the same when assembled and being every bit as mechanically sound. Like a carcase dovetail, it mechanically resists loads well in one direction, and requires glue. I’ll do these momo-pattern joints in a future piece. It might be worth exploring the cut out process using a table saw with a specially-ground blade if there were a lot to do.
All for today. I should have the carcase of this bookcase together in another few hours of work, and then I can start in on the frame and panel back, which will be made from some bubinga left-overs. I won’t be gluing the shelves of the carcase in place, only the wedges which locks the multiple tenons – that will make the assembly process a fairly non-stressful affair I think. The momo-gata joints I will glue however. Minimal use of glue is a good thing I think.
Thanks for coming by on your travels! –> on to post 3