Horia: I would suggest to measure the distance of the gap, or hole. Then measure the distance of the part that is going to be inserted into that hole. Then do math. Divide both by 2 then subtract. That will give you the remaining distance that is considered the "play" of the parts.

So looking at your image... Say the hole that the cylinder goes into is 10 mm, and the cylinder is 9.8 mm. This means that there will be 0.1 mm of play on either side of the cylinder.

Then you have to take into account the tolerance of your printer. If your printer is consistently putting out larger parts... chances are that the cylinder will fuse to the hole. If it produces consistently smaller parts... you should be fine.