Here is a drawing with dimensions of the “L” brackets used to hold the edge connectors in the expansion chassis. Note the .75″ spacing of the cassette cards. That is a pretty standard dimension that was used for card spacing back in the old days. The backplane uses the same spacing. SCELBI used #4 screws and bolts with no washers to hold these in place. I’m thinking of using 1/8″ rivets instead. A machinist chart shows the clearance hole drill for a #4 screw is from #32 (.1160) to #30 (.1285). I think a 1/8″ drill bit would do the trick.

Expansion Chassis Brackets

Since I have laser printer decal paper on hand and a laser printer, I’m going to try to make the lettering with decals. If it doesn’t work well, I’ll try getting some custom dry transfers made.