The Chair – Tenons
The build would be a lot easier if The Chair used straight stretchers throughout its construction.
The side stretchers do each have one skewed tenon, however this is no more difficult than a straight tenon.
It is the front and rear stretchers that gave me fits. They are not just curved in two dimensions, but also taper at the ends.
In addition, the shoulders of the stretcher tenons need to be coped to fit flush with the round leg. If you look carefully you will notice that the coped shoulder is not symmetrical. As a result of the taper, the ends are asymmetrical.
How to set this up to saw accurate tenons?
The answer lies with the templates that were made earlier on.
Below is a picture of a set of templates attached to a stretcher.
You may notice that the ends of the upper template have been coped. A line drawn across the ends – below – marks the shoulder of the tenon.
I am satisfied with the accuracy of the marking out. I checked to see whether they matched on each end …
… and they did.
The question I asked the forum was how you would go about coping the ends?
Step one – slice the edge template in half. Cope one end.
Then cope the other end …
… and tape them together at the centre …
While not absolutely necessary, the tool that makes this easy as pie is a contour gauge …
Transfer the marks to the template …
… and use a gouge to whittle away the waste …
Tenons
What we have at this point is the shoulder for the tenon. We now need is to mark and saw the cheeks.
This is one time we need to centre the tenon on the stretcher, as the mortice will be centered in the leg.
For this I used the mortice-marking gauge I built recently (yep, we laughed about it as it was a little OTT, but I did say it might come in handy!).
The mortice is 3/8” (9.5 mm) wide mortices. That seems to fit with the photos I examined and roughly in association with the 1/3 Rule. Below the position is being established with a 3/8” chisel.
Rather than a double-bladed mortice-cutting gauge, I chose to use two single cutting gauges (Veritas wheel gauges).
The cheeks were marked from the concave side.
The shoulder was undercut to aid in sawing the shoulders.
Owing to the curve of the stretchers, they could not be used on a bench hook. It was easy enough to saw against a couple of dogs with the help of a hold down.
I have found the ideal clamp for sawing tenons is the end vise.
Saw one side of the cheek ..
.. and then the other …
The first part of the tenon is now complete.
The tenon still requires quite a bit of work. However, before further shaping is attempted, the mortices must be cut into the legs. The tenon shoulders cannot be coped until they have a matching mortice.
The mortice used in The Chair looks like this. It is stepped designed to enable two legs to intersect the same section of the leg.
The matching mortice looks like this …
Below are completed stretchers. They are slotted for Danish Cord (#501), where as the stretcher above is rebated for a seat (#503).
Tomorrow I shall begin the mortices. How would you make these with just hand tools?
Regards from Perth
Derek
January 2014