On 2007-12-10, Bill Schwab wrote:
DoN,
Does that change how you would scribe the lines?
Not too much -- except that I might look for index plates and
arms to fit the rotary table instead of depending on the dials. The
rest I would do as I just described in the followup to a previous branch
of this thread. (I'll plead laziness for not typing all of that again. :-)
[ ... ]
In partial reply, I have index plates for the table, but it looked to me
like something that was intended to be used in the vertical orientation
(axis parallel to the mill table)???
The most common use is in cutting gear teeth on an arbor between
the table and a tailstock, but there is no reason why you can't use the
plates and arms with the table in the horizontal orientation as well --
as long as it does not hit the table. And even then -- you could make a
riser block to avoid this problem.
The truth was I needed the table,
recognized the potential value of an H/V, and the indexing setup was
cheap enough that I bought it figuring I'd use it some day. I have not
taken time to research exactly what I bought. I more or less get the
idea of index plates and at least some of why you recommend them here.
I *think* that your table may be a 90:1 ratio, so you get four
degrees per rotation of the crank, and you can use any index plate which
offers a circle of holes which is a multiple of four, and probably the
smallest multiple of four would make the proper hole easier to hit.
Anyway -- five degrees would be one and one quarter rotation, one degree
would be 1/4 rotation, and ten degrees would be two and a half
rotations.
If your worm gear ratio in the table is different, then these
figures all change, of course.
What is not clear is whether I can use them with the table horizontal,
which I _think_ is the correct way to scribe the lines in question.
You should be able to. And yes -- horizontal is the way to go
if you are using a half-round Vee tool as suggested by someone else
yesterday. But you have other ways to do it, too. One way would be
with the edge of a dovetail cutter with the head tilted half the
included angle, in which case you would use a vertical setup so you
could move the cutter along one side of the plate which you are cutting
-- parallel to the center height.
In my case, I would be using a horizontal mill, and probably a
conventional milling cutter with a sharp V to cut the lines --though I
could come in from the side with the half-round Vee from above -- or
from above with the vertical adaptor in place. In any case, I have bed
stops with micrometer adjustment, and lever feed, so I can cut the
shortest lines first, adjust one stop back an appropriate distance, cut
the medium lines, and adjust it back again and cut the long lines.
More dumb questions to come 
Keep asking. Others learn as well when you ask, and answering
the questions makes the process clearer in the minds of those who are
answering.
Enjoy,
DoN.
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