Bought some "Carbon" drill bits. They cut like nobody's business in the rear tube cap. Also put my new "Vermont" taps to work- both holes are 10 x 32. Found a piece of blue plastic, and cut off a bit, and dropped it into the set screw hole. Seems to work...
Neither hole is straight. I intentionally tried to angle the adjuster screw with a center-ward slant The set screw is off kilter too. I did these by hand, and it shows. I still have to figure out a way to rebate the "inside" part of the tube cap. I'm thinkin time to break out the diamond cloth again...
Regards,
Doc Sharptail