The rear/center slide rail is fabricated from two pieces of aluminum to form a T rail. The base of the T was pre-bent. I had to cut a piece of aluminum sheet to form the top of the T. Then I had to drill about 50 holes in the sheet on 31/32" centers. Fortunately, I was able to get the Rivet Fan working to lay these out. After drilling, I then match drilled the sheet to the bar to form the T. This all went pretty well.
After getting the basic slider joined with Clecos, I went back an drilled lightening holes between each of the rivet holes. This seems like a lot of work for the benefit, but it does look good.
I primed the parts and counter-sank both sides. I then did a flush/flush rivet of the two pieces. That came out great.
From there, I drew a centerline down the upper skin and laid the slider in place.
I drilled the UMA pieces C661 and C806. I am not happy with either. The prints were incomplete with the dimensions. The slider block must be replaced, so I decided to replace both.
I moved on a built the side rails. These went pretty smoothly. However, it seems that the plans have the left and right reversed.