[Gordon Steadman]

You still haven't convinced me that it is straight forward! But I can see that having an 2440 x 1220 table to form the sub-structure is a big help.

What size router bit did you use for the slot?

The sub structure is just square section wood and the ply is screwed directly to that before cutting the slots - taking care not to put screws where the slots are going of course! The 1mm left after routing is enough as the frame gives good support.

I used a 4mm router cutter. In some ways, I wish I had gone to 5mm as the modern SlotiT wood track guides bind a bit at the hairpins. Might ease the slot or reduce the length of the guides.

Blowing that old trumpet again, a track like this is simple stuff compared with what I did for a living. I was a professional chippie making hand made kitchens and guitars etc.