On Sun, 08 Jan 2017 19:23:11 -0800, whit3rd wrote:

On Sunday, January 8, 2017 at 5:42:13 PM UTC-8, Phil Kangas wrote:
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

So, bore the hole 2.5", hold from inside, complete the taper,
hold from outside, and finish boring the hole.

Is that intended for lathe setup, or mill? Why not just cut the
3" ID in the first place?

As I read the question, the disk will end up 0.375" thick at
one point, and about 0.2005" at a point 5" from the first point.
Phil doesn't say if the OD edge should be perpendicular to a
plane that bisects the finished item, perpendicular to a
remaining original face, or perpendicular to a single new
face.

0.2005 = 0.375 - 5*sin(2 degrees)

--
jiw