I'm trying to mill a conical hole using CNC. I'm having trouble programming
a helical cut using and end mill. As it's sunday I can't pick up a tapered
reamer to fit my needs.

Here's the geometry:
0.5" thick mild steel
0.5" diameter hole on top, 0.375" diameter at bottom on XY plane.


Here's the problem:
Use a 3/8" ball mill to make this hole. The hole has been pre drilled.

Anyone have any G-Code samples to make this hole?