On Dec 9, 10:26 am, Bill Schwab wrote:
...
The bottom line is that an 8" RT will be in the horizontal position, and
the lines will be scribed on a plate clamped flat on it. The RT's dial
will do the indexing.

Does that change how you would scribe the lines?

Bill

I'd first try a half-round conical cutter, probably hand-ground from a
broken tap and finished to run centered with a Dremel on my easily-
cleaned 6" lathe. Spinning it in a drill while grinding works pretty
well too.

My RT can be adjusted for worm gear engagement but there is one extra-
tight area so I need to run it around once as a test. I've learned to
ALWAYS tighten the clamp before cutting.

Jim Wilkins