Part 8 - Glue up

Today we reached the milestone I was patiently (okay, not so patiently) waiting for - gluing up the legs and seats. To get to this stage, however, required matching the mortices with the loose tenons, matching the loose tenons with the leg mortices, cutting slots for the wedges (into the tenons), and shaping the tenon mortise to fit the legs.

Let's start with the obvious. This is how the tenon and the tenon mortise will end up looking ...

The loose tenon is 30mm wide and 10mm thick. It extends 28mm into the tenon mortise ...

This all looks rather neat, but it was the end result of further shaping to fit the legs with the seat. The issue was that the seat mortices were chunky ...

When joined, this was the fit ...

Two steps were involved. Firstly, the tenon mortise was reshaped to be thinner at the face (this involved removal of waste at the top edge and not the sides, which is needed support for the loose tenon) ...

Secondly, the face of the leg mortise was planed flat to match the face of the seat mortise ...

This is how the original chair was fitted - photo I posted early on ...

This is the result ...

All the parts fitted, but not yet glued up ...

Loose tenons slotted for wedges, along with the wedges. Glue of choice: Old Brown hide glue. Why? Because at some stage in the future, hopefully many years from now, it is likely that the joinery will need to be re-glued.

The seat tenons are glued first and the glue allowed to dry (they are a bit long here, and were cut shorter before the legs were attached) ...

And a last photo of the final glue up. It will remain so for 24 hours.

Starting to look like chairs!

A Note about Wedges

On the Australian forum I was asked for more information about the wedged through tenons.

I am not sure if the photo provided must detail, but the wedges are tapers, but also long and skinny ...

They both fill the slot - which is full of glue - and create a wedging action, firmly pushing the tenon edges against the glued insides of the mortise. The mortises, both in the seat and legs was 30mm long. Most were exact, some of the legs were a little under a mm long. A little filing for all to create this tiny gap - it does not have to be more. The glue is enough and the wedges are security. Interestingly, this appears to be the same in the original chair, with the exception that they added a chamfer for the end of the wedge. I've never seen this before ..

In addition to the wedged legs (I am trusting that the small amount of taper inside the mortises will add an extra layer of solidness), the arm/back structure adds stiffness and resists the legs wracking/moving. It is akin to triangulation of the construction (not really triangles, of course).

I have removed the clamps and the structure is really stiff already - I will wait until Lynndy is out of the way to take some photos. She-Who-Must-Be-Obeyed is keeping a steely eye on my "taking it easy" today! [Explanation: I was in hospital yesterday for an op on my left torn patella]

Later:

I snuck into the workshop to unclamp the glue up. Lynndy caught me! But she then asked to sit on one of the chairs (sans the arms and back). She did so gently, and then with all her weight (55Kg). The seats did not even sigh, and nothing moved. She proclaimed the seat very comfortable. Yay!

Tenons and wedges yet to be cut and levelled ...

Regards from Perth

Derek

March 2024