Screw spacing for TC Contender rear sight

[ohland]

First pass, two pairs of holes, .31 inch apart, .835 inches between the pairs.

Distance between outer holes, 1.455. Taking more measurements. Trying to figure out a jig to mount a TC silhouette rear sight (the Williams FP type).

I had an old Single Shot Exchange where someone did the measurements needed to make a FP base, but I never scanned that issue... Sigh.

[ohland]

Ever the inquisitive metal monkey, I tried sliding the Williams riser into the T/C silhouette base from the bottom. It fits. Tried again from the top, slightly tight at first, but after the first 1/8 inch or so, it slid down until the elevation screw hit the top of the T/C base.

OK, now to figure out the best, er, easiest way to go from the T/C thread of 6-48 to the Williams thread of 6-40....

[ohland]

With the arrival of the needed ER32 collet and a 13/16 drill blank, I dug out my replacement DRO scale, and snap! The cunning chinese struck again! The linear encoder beams are different width. So I pulled the guts from the new scale, fastened them on the beam, and found out the PCBs are different... The original scale has the encoder grid covered with green resist, and the surface of the PCB is the same, side to side.

The new scale has the green resist layer removed on both sides of the encoder grid, .020 inch lower than the grid itself. So using the original brass spacer strips and tightening the case together results in the case being too tight to move....

Went to Ace, picked up a piece of K&S Engineering brass strip, 1/4 inch wide, .016 thick, 12 inches long. Snipped two shims, cut out a notch on one end, cut the other square, then placed the original brass spacer on top. Did both sides, gave me @.021 inch spacers, and the slide moves along the beam.