"Jim Wilkins" wrote in message
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"Phil Kangas" wrote in message
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I've been presented with an unusual project involving
cutting a 2 deg taper on one side of a disk. The part
is mild steel, 3/8 thick, 5" O.D., with a 3" hole in the
center. Guy wants a 2 deg tapered face across the
disk. That's starting at 0 at one point to doc 0.174
at the opposite side of the 5"o.d. . How would you
do it? Mill? Lathe? How to hold it? Will a four jaw
chuck hold it safely? I'm a bit leery ....
phil k.

I'd clamp the square blank to an angled fixture on the mill table.
The fixture could be a bar with a narrow step 0.1746" high, plus
thinner intermediate supports slid in until they jam. A small center
hole would allow redrawing the circles to know how close to the
clamps you need to mill and then to bandsaw the blank roughly round,
and help center it on the lathe.

You could use a 3/16" (0.1875") spacer such as key stock or lathe
bits if the distance between the contact lines is 5.369". You need
to mill two edges of the blank parallel at whatever width the spacer
height requires anyway.

--jsw

The same setup would work on a lathe faceplate but I'd hold the blank
with screws in countersunk holes to avoid the rotating clamps.

-jsw