Part 8 - Arms - part 1

The key piece is the top rail, and the key element here is the rear curve. Here it is smoothed on the belt sander. It will be a reference side for marking curves ...

The angles I have had to guestimate have been the tilt, front and rear, of the top rail. This is what I came up with ...

The plan is to join the arms using dowels. The Rule of Thirds applies. 3 x 3/8" dowels (3/8" = 9.5mm, which is close to the 10mm tenons used previously). Why dowels? Because they are easier to position accurately without a reference edge.

Since a large amount of waste will be removed from the top rail and arms, through shaping, the dowels need to be positioned where they will not be cut into. The three marks on the ends of the top rail are the position for the dowels. The wooden block was a quick guide to drill vertical as it needed to be done freehand ..

The only complication was that I had 6mm dowel centre points. It would have been easier if they were 3/8". Nevertheless ...

Drilled for 3/8" dowels in Jarrah (I have a bucket of them), each close to 50mm (2") in length.

Everything is still a rectangle at this stage ...

The inside face of the top rail is shaped ...

It is at this point that I have a re-think about the curve of the rear - it is not a fair curve and enough curve when compared with the photos of the DC 09 chair. The re-drawn curve on the left looks correct to me now, and this is what we will go with ...

The parts are joined up as a loose fit (using undersized dowels)...

The arm/rail combination is now placed on the arm supports and adjusted to the front and rear to determine the rear overhang and position for the front joint ..

The template I made up earlier is used to trace out the side elevations. The shaping here is approximate. The main goal is to establish the length of the arms and from arm support joint ...

A little detail of interest: the height cut is slightly more than the front joint triangle would suggest as the final shaping requires a little extra meat to end in a curve ...

This is now sawn to shape, except for the underside of the arm, as the mortise/tenon area needs to be determined separately for each arm ...

Tomorrow will begin the final shaping and, hopefully, glue up of the arms.

Edit to add

A little more as it is getting closer.

The first step is to align all the arms and mortices ...

There was a lot of scribing, fitting, scribing and more fitting.

Finally the shaping of the underside of the arms was possible as it was now possible to determine the general position of the mortises.

The waste was removed with a bandsaw and coping saw ..

Now the specific position for the mortices was fixed with dowel pointers ...

Drilled and dowelled ..

And the arms fitted to check that all will fit at the end ...

Shaping to come.

Regards from Perth

Derek

March 2024