2D Adaptive Clearing and No Toolpath on a simple part (File Attached)

[RedMonkeyMakers]

I'm trying to learn about Adaptive Toolpaths and wondering if someone could give me a hint on why the bottom of the counterbore hole can't be done using adaptive clearing.

The top of the bore works fine with Adaptive Clearing and the 1/4" bit. 

The bottom using a 1/8" bit (4mm hole) is having problems.  Is it because the hole is not wide enough to do adaptive path?

[HughesTooling · Accepted solution]

Changing the tolerance to 0.01mm allows it to calculate but not sure adaptive is the right toolpath for this. Personally I'd use bore so you get a hilical cut.

[RedMonkeyMakers]

Thanks Mark!  I indeed did use the boring toolpath when I cut the holes on my CNC table.. I was more curious as I'm learning about Adaptive.  I'll read up on tolerances.