I ran the program to cut a 1.335" hole into which the eyepiece extension tube will slide. Then I removed the workpiece from the vise to verify a good fit. Not tight not loose. Then I put back in the vise aligning it to the edge of the vise jaws so that I was back to X=0. Then I ran the program to cut the 2.01" hole to slide this tailpiece into the tube. I was not quite on 0 and the two circles were not exactly coincidentally centered.
Okay, I will put it in the lathe and trim the outer edge to get it centered. This turned out to be very difficult. (I was still waiting for my 3" lathe chuck to get back from Sherline. The 2.5" chuck is just barely capable of holding the workpiece with so much center discrepancy.)
So, I had destroyed my last 1" thick piece of Delrin. I tried again with a .5" thick piece. For reasons unknown, the mill threw the workpiece and mill vise onto the desk Somehow I salvaged the workpiece enough for another pass although it was ugly from being thrown around by the mill.
Worse, the outer circle was not regular but I was able to trim it on the lathe to dimensions that barely slide into the finderscope tube. I trimmed the end so that I had .247" releaved enough to drill and tap three 6-32 holes at 120 degrees apart. By very carefully use of the edgefinder I was able to put through holes at the end of the finderscope tube that exactly lined up to the tapped holes.
Last step today was putting a threaded hole in the 25" of the tailpiece to let me use a thumbscrew to hold the eyepiece extension tube in place. Of course this is too small for the 1/4"-20 thumbscrew I have. I did find some M4 thumbscrews in stainless; the extension tube is CFC. Of course, I have an M4 tap, but the M4 thumbscrew is a little short. Home Depot's fasteners guys did not even know what a thumbscrew is much less have one in stock so waiting for Monday delivery by Santa Amazon.
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