I Thought These 3/16" Carbide Endmillls Would Be Brittle

Yes.  I am attempting to see if I can cut fine lines as degree markers.  The plan is to make very fine lines, apply some acrylic paint to fill them in, and wipe away the rest.

How deep?  I have the mill cutting 3/16" thick lines at .01 through .1" deep. 2" apart.  I was a little too aggressive.  I cut .04" deep at 4 inches/minute and snap!  I have gone down to .5 inches/minute.

The temptation is to use HSS endmills.   They will not last as long but they are less brittle.

UPDATE:

Yes, 3/16" is too wide.  1/16" HSS endmills are scarce and mostly have 3/16" shanks.   The only Sherline 3/16" endmill holders turned out to be .235" ID, so not useful. I have another solution,  printed not cut which I will post soon.

T

It being written in PostScript, I can size it as I need, then laminate on.  Making it fit a three inch radius circle and still be readable is harder than I thought.  I may need to make this a larger radius.

Oregon Rule Co. makes more and more sense.