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. So a 3mm hole should shrink down to 2.7mm, a 2 cm ring will shrink by .5mm, and an 80mm disk will shrink to 79mm. Of course your milage will vary, but this equation was intended for you to guess right more often the first time.