3D Prints and (semi)precision sizing: Do I need to offset surfaces?

So I’m doing up a quick 3D print of the second half of the Hive logo as a quick holdover for the BeeBox. I remember Ryan talking about how he had to offset a surface or something due to the plastic squishing out. Is there a value anyone can name as a rough guide for how much to offset the surface to guarantee it fitting, say, over a screw rod of a specific diameter? The fit doesn’t need to be tight, in this case, just enough to guarantee fitting over it.

Specifically, in this case, it needs to fit over the thread of a 10-24 screw, which has a nominal dimension of 0.1900". (As of writing, I haven’t actually taken calipers to the screws… Bad me. Go sit in the corner.)

Files on Dropbox:
SKP: https://db.tt/E8okVTx4STL: https://db.tt/UpbiCxlT

PS: I’m currently not certified to use the 3D printers, so either I’ll need for someone to print this or I’ll need someone to take me through the process of not breaking/ruining-for-others the printers so I can use them.


This gets printer-specific in a hurry. I’ve always found Gigabot prints slightly oversize, and have had good results with scaling prints (in Slic3r, not in the model itself) to 98%. The Polar3D prints true to size with much less hassle. In either case, I generally create a very thin/flat test sheet and print it a few times to dial in the scaling factor if exact sizing is important.

Another approach with mounting holes is simply printing them undersize with a thick perimeter, and boring to the final diameter on the drill press.

  • Ry

Darn! Guess I’ll just have to print it and see if it works.