Drill hole test cube

This is a test print for flat-top screws/bolts. There are 2 holes, one transverse to the layers an one parallel to them. I had a big project with 24 countersunk holes, but i needed to check that they were the right size before wasting hours on a test print. I mocked this up, and it was what I needed. The cube is exactly 3 holes wide, so scale the cube to 3x the size of the hole you want to test.

Me personally, I have found that prints shrink by .2-.3mm + .1mm per 10mm of the outer dimenstion.