Front Seat Diaphragm Partly Installed

At about 8PM last night I went out to the garage. At 10:10PM I came back inside.
It doesn't look like two hours worth of work but there was a lot of fiddling around to get an approach right. I took the picture this morning and Xena (the rag stealer has a name) was puzzled by what I was doing.

The Triumph TR6 rubber diaphragm is secured at the front and back. I have yet to drill the holes in the side pieces of aluminium (you can see them at the front of the seat on the floor).

Close up of the front. Note the special holes near the middle to relieve the lateral pressure on the aluminium. Nah - I just stuffed up. For some reason the calculations were out by about 5mm so there wasn't enough stretch so I drilled new holes. It's a bit off centre but it won't matter.

I had to use 32mm wide aluminium on front and back but the sides will be 40mm. I really need about 45 mm because the holes will only be 7mm from the edge. It'll only matter in about 10 years if the steel links elongate the holes in the aluminium to the point where it gives way. The aluminium is as wide as I can make it to help support the 50mm foam that will form most of the seat cushion.