27th Jan 2010, 03:10 PM #1
Cutting a Mortice and Tenon Were the Tenon has a Curved Shoulder
I have been looking at constructing a variant on the Round Chair other wise known as The Chair by Hans J. Wagner the mid 20th century modern designer, in particular I have been looking at how the rails join the legs. Were the round legs meet the rails the shoulder of the rail need to mate perfectly with the round legs. To achive this means that the shoulder need to be round.
I am interested in any and all process how this can be achieved.
As far as I can figure, you would make the rail first, by using a router bit to route out the round shoulder shape, then turn the leg to match perfectly. Then join the two using a floating domino style tenon.
Skip the shoulder shoulder completely and use some kind of bare face tenon.
While it is not the method used by Wagner as it is give a diverent look is to keep the stock sqaure, then to cut the M&T for the leg and rails and then to round the stock after the joinery has been cut.
If anyone has any suggestion they would be most welcome.
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27th Jan 2010, 03:55 PM #2Member
- Join Date
- Feb 2008
From a complete novice
Why could you not recess (very shallow mortice) the face of the leg to the shape of the rail, then use the domino.
Sounds easy, but I bet it's not.
Just a thought.
27th Jan 2010, 03:58 PM #3
I see what you mean. That would be another way. Solving the need for having a round shoulder.
27th Jan 2010, 05:16 PM #4
Brizylad's way is the way I've seen it done. An alternative would be to shape the end of the rail by carving to fit the leg and use a loose tenon. You'd have to be careful to get everything accurate though. Probably cut the mortices first, then shape it with the loose tenon in place.
29th Jan 2010, 02:38 PM #5
TS - I've done this sort of joint several times when joining legs to a table pedestal. You simply cut the tenon, or sliding dovetail, then use an in-cannel gouge to shape the shoulder. On a table leg, you have the option of hiding the top of the joint under a lip turned on the leg. This means you can undercut the shoulders more than the curve of the boss so that only the outer parts actually make contact with the curve, making it easier to get a tight, clean line.
However, for a joint in a smooth cylinder like these chair legs, you have nowhere to hide, so the radius of the shoulder would have to match the leg radius exactly. You could do it, but it will be a tedious & finicky job, and I would not like to be doing it for a whole set of chairs, even if the customer were prepared to pay for the time involved!
Wegner's chairs were designed for factory production - the legs would have been turned on a copy-lathe to tight tolerances - the rails would have been batched & run through a shaper to cut tenons & shoulders in one pass, and the whole thing could easily have been assembled by trained gorillas. There are designs that lend themselves to hand manufacture, and designs better left to machines.
BTW - these chairs look great, but are 'orrible to sit in for any time. That wincey little back rail is cleverly designed to hit you right on top of a single vertebral process. We had them in the meeting room where I one worked - we got through the agendas in zip time.....
30th Jan 2010, 10:46 AM #6SENIOR MEMBER
- Join Date
- Oct 2001
I made a coffee table once with rounded legs with square sections morticed into it much like the chair. It also had a sub fram that was square. the whole thing was based on shoulderless mortice and tennon.
I just square morticed all the frame parts into the round surfaces (legs). No need for dominos or shoulders or other messing about, but in other respects you had to be very carful with tolerances. Good luck with it, maybe they encourage you to be complicated with what do in your course there, Keep it simple I say.
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