Saturday, February 12, 2011

Ming Inspiration (32)

Welcome back to those readers who have been following along this build of an all-joined, glue- and metal-free frame-and-panel dining table. The influence is 16th century Chinese, and the wood African bubinga. Previous episodes, for those of you who are first time visitors, or who may have missed a few recent postings, are archived to the right side of the page.

Continuing on then with the work on the Giant's Arm Braces, or banwancheng. The next maneuver was to cut a blind mortise on the lower 'tenon' end:


These mortises will receive a stub tenon from the locking, '+'-shaped sliding splines, already described quite a while back, though those stub tenons are not cut yet.

On the lower surface of these brace 'tenons', I cut a rebate, which will be part of the means by which the brace locks to the table leg:


I cut the shoulders of these using the table saw, in interests of consistency, my aim being a finished length of 1.0050":


Nice to meet one's aims once in a while, though maybe a bit lucky to hit the number exactly.

All four braces now are complete at their lower joins:


It was fitting time for a fitting session, if you follow. These joints, due to their beaked profile and central locating 'tenon' are exactly the same sort of kettle of fish as the sword tip miter fittings described recently - kinda nightmarish. I need to be cautious fitting these given their critical dimensions for assembly and direct relation to the leg perpendicularity - and with the braces being curved and inclined, and on a 45˚ plan axis, there's certainly not a lot of room for any miss-cutting. No, no mistakes allowed!!

Here's the initial presentation of one brace to one leg:


As you can see on the top face, there is a bit of a gap between one of the 45˚ cheeks of the brace. So, some work is needed. I left them a little fat, so there is room to play. The amount of play room is seen in the space between the end of the brace 'tenon' and the back wall of the slot, @1/32" or so at most.

My tools of choice here are a Japanese saw file;


And of course a thin paring chisel:


Trying the fit again, you can see that gap has been much reduced:


The line on the other meeting between the brace's mitered cheek and the leg's face isn't too bad at this stage, but does need a little more fettling:


While re-shaving the inside cheeks of the beak, I also take the opportunity to check the inside of the mitered 'beak for squareness. I used my gauge block, which is a perfect 90˚ at it's corners, pressed flat against the 'tenon':


Another trial fit, and you can see that the relationship between these parts is getting friendlier:


Just a step back to look at the overall fitting situation and parts relationship:


Satisfied eventually with the fit of the brace to the leg, the next move is to bore out a stepped seat at the bottom of the slot, to accommodate that stepped tenon on the end of the brace:


Next followed and all-out assault with at least 4 different chisels to clean up that stepped seat as best I could. Hard on the chisels that was!

Once the stepped seat was done, I tried the fit, and was pleased to see the brace snug down there nicely:


A view from the other end:


As you can see, this mechanism is a little involved, but I think it will make for a much stronger connection between the banwancheng and the leg, as compared to the usual classic Chinese furniture technique of a half dovetail and glued infill plug (which is nothing to sneeze at, BTW).

All for today- thanks as always for taking the time to explore the Carpentry Way. --> on to post 33

No comments:

Post a Comment

All comments are moderated, so if you're planning to spam this, know now that your clicking and pasting is in vain. I do read the comments before posting, so your mission is doomed from the outset. All this time and effort trying to put your inane spam onto blogs -- is this how you want to spend your time on earth?

Please do me the courtesy of appending your name to your comment, even if posting under the 'anonymous' option. No name = deleted.

Comments NOT accepted include:

-those containing links unrelated to blog content
-spam of any kind, or ham for that matter
-did I mention that attempted spam postings will be non-starters?