The Chair – Fitting the Front and Rear Stretchers (Part 2)

I took many … too many photos during the fitting of the front and rear stretchers. In the end I had to ask myself what was the point of this? What would be helpful and interesting?

The front and rear stretchers differ from the side stretchers in that they are compound curves. Still, the process of coping the ends is the same for both, and the only part that is more complicated is getting the mortices lined up.

The first task was to check that the tenon shoulders were square. I had gauged these when building the templates, but I was not happy. Two of the four were not square. Even Blind Freddy could see that. They were fixed here.

Now I could line up the tenon with the centre point of the leg so conveniently created when turning the legs on the lathe.

The tenon was traced onto the end, which may be seen was off the square of the end block. A line was drawn square with the tenon, and then cut away at this point.

This arrangement made it possible to lay the leg on the bench top with the section for the mortice situated in the vertical. A line from the centre of the tenon to the centre of the foot made it possible to accurately locate the position of the mortice.

I shall not subject you to the mortice being bored and chiseled again. However you may be interested to see what the interlinked mortice looks like ..

Rotating a leg … the mortice for a side stretcher (the right side faces towards the floor) …

Continuing clockwise …

… and finally we see the mortice for the front stretcher …

All the mortices were made and the tenons fitted pretty well. None of this constitutes mating the tenons with the mortices, however. More on that in a short while. However, we are looking good at this stage …

Now the hard work begins!

I thought that I would post a few observations and tips when coping the curved stretchers with my now vast experience (gained earlier in coping 4 ends!). So here is a summary of the procedure that I developed for this task.

Working on these stretchers was made possible by having saved the offcuts from sawing the curves ...

The shoulder curve was transferred from the contour gauge ..

Super glue was applied to all corners as the Jarrah is brittle.

The tenon cheeks were extended down to the curved shoulder line …

Before using the gouge, remove as much of the waste with a narrow chisel. The edge of a curved gouge is more work to sharpen than a straight chisel, so save it for the work it does best …

Now remove the waste to the line …

Remove as much of the waste at the straight shoulder. I used a ¼” bench chisel …

Now, working from both ends, I used a 1/8” bench chisel to rough out the curved shape. An effort is made to maintain a coplanar line along each shoulder.

Now refine the shoulder with a narrow gouge …

Since the tenon shoulders have been lowered, an equal length must be sawn off the end of the tenon cheeks.

After all this was done, the two parts (stretcher and leg) came together. A slight gap was evident at the front as well as a blunt corner …

This would need to be corrected by coping the shoulder a little more.

It is also necessary to check the shoulder for straight – which is evidently not the case here …

Straighten with a shoulder plane, and pare/cope the shoulder some more.

Eventually you get a perfect fit.

Or so you believe!

The legs and stretchers are brought together …

It is looking good … again.

However, now we begin tuning the fit. This will separate a good fit from a great fit.

Compare the diagonal lengths from the centre of one leg to the centre of the other leg on each side.

I used a clamp to pull them into equal lengths …

What this showed up was a gap at two joints …

The fix will be to remove a sliver, as marked by the white line ..

This process will continue until all joints are a good fit.

Next time we finish the stretchers. Yes, there is still more to do (sigh).

Regards from Perth

Derek

January 2014