Calibration and fit
3D Print Hole Size Compensation: Make Holes and Pins Fit
Calculate starting hole and pin dimensions
A hole designed at 10 mm does not always print as a clean 10 mm hole. Extrusion width, curved perimeters, cooling, shrinkage and feature orientation can all reduce a printed diameter. Scaling the whole model is usually not the answer.
Start with the fit you need
Loose clearance, sliding motion, a snug lid and a press fit need different gaps. Decide whether the hole passes a bolt, guides a pin or grips a part permanently, then model dimensions for that intent. The Tolerance & Clearance Calculator provides a starting CAD dimension from your own test print.
Measure a simple test
Print several holes and pins near the sizes you use, with the final printer, material, nozzle, layer height and orientation. Measure with calipers and note whether holes are undersized, pins oversized or both. Consistent whole-model error belongs in the Shrinkage Calculator; feature-specific error belongs in clearance or hole compensation.
Check surrounding geometry
Thin walls around a hole can deform or slice poorly. Inspect them with the STL or 3MF Wall Thickness Checker, then verify line count and orientation in the slicer.
Practical cautions
- Drilling or reaming may be better for precision holes.
- Horizontal and vertical holes can need different compensation.
- Flow calibration makes extrusion more consistent but does not remove the need for clearance.
- Record successful values by material and profile.
FAQ
Why are my 3D-printed holes too small?
Perimeter width, curved paths, cooling, shrinkage and feature orientation can make holes undersized.
Should I enlarge every hole by the same amount?
Test the relevant size range first. Small holes often behave differently from large openings and the desired fit matters.