Print-in-Place Tolerance

Hinges and captive nuts only work if the gap survives your printer’s error. Measure a test coupon, pick a fit, and split the clearance between hole oversize and shaft undersize.

Inputs

Units

Results

Designed clearance: 0.650mm
Add to hole / slot: 0.325mm
Remove from pin / shaft: 0.325mm

Recommended gear

Digital caliper
Measure the coupon, not the slicer preview. PIP lives and dies on tenths of a millimetre.
Typical range: $15–$40
CoreXY printer
Tighter XY error shrinks the required gap. Z still needs the 1.4× penalty.
Typical range: $300–$1,500

Calculation method

Start from a measured dimensional error (how far a printed 20 mm bar missed 20 mm, or the gap that just fused). Double it so both sides of a mating pair can be wrong, scale by 1.4 if the split is in Z, then add a fit allowance: 0.05 mm press, 0.25 mm sliding, 0.45 mm loose hinge. Half of that clearance goes to the hole, half to the shaft, so CAD stays symmetric. Values are millimetres; imperial shows inches.

Exact formula

clearance = k × 2 × tested_tolerance + fit_extra. k is 1 on XY and 1.4 on Z. Press extra 0.05 mm, sliding 0.25 mm, loose 0.45 mm. Each side of the pair gets clearance / 2. Limits: Heuristic extras. Elephant’s foot, wet filament and a different nozzle eat clearance. Print a hinge coupon before a 12-hour job.

Coupon before the real part

A 15-minute hinge coupon with three gaps (tight/slide/loose) teaches more than this page. Change filament? Reprint the coupon.

Frequently asked questions

Why not put all the gap on the hole?

You can. Splitting it keeps both features closer to nominal and is easier to remember.

Press fit on FDM?

Possible on XY with a well-tuned printer. First-layer squash will still glue a Z press fit.

Elephant’s foot?

Chamfer the first two layers or add 0.2 mm extra on Z gaps that sit on the plate.

Do I need this for screw holes?

Use the heat-set insert tool for brass. This is for printed-on-printed motion.

Disclaimer — no professional advice, no liability

Elephant’s foot, elephant’s skin and wet filament all eat clearance. A 0.2 mm coupon on a 0.4 mm nozzle yesterday is not a warranty tomorrow. Print a hinge coupon before a 12-hour print.

These calculators, pages and any related content are provided “as is” and “as available”, solely for general educational and informational purposes. They are simplified mathematical estimates, not firmware, slicer profiles or a production quote, and they do not constitute engineering, electrical, chemical or other professional advice.

Results can be wrong, incomplete or inapplicable to your printer, hotend, resin, material, firmware or use case. You must independently verify every figure, assume all risk, and confirm settings on a test print before a job that can damage a machine, start a fire or injure someone.

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Print-in-Place Tolerance

Inputs

Results

Recommended gear

Calculation method

Exact formula

Coupon before the real part

Frequently asked questions

More in this topic

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