Printer calibration coupons: hole, pin, nut-trap, T-slot tongue and bearing-pocket gauges — dimension sheet
Source: Xem Studio, https://xemstudio.com/objects/printer-calibration-coupons/  (CC BY 4.0)
Basis: Every file on this site assumes: pivot hole = pin + 0.2, press fit = pin − 0.05, bearing pocket = OD + 0.2 (OD + 0.3 above 20 mm), nut trap = AF + 0.3, T-slot tongue 5.8 in a 6 mm slot. These coupons find your printer's offset so those assumptions hold
Catalog version: 2026-10-20

Sizes: see table below
- Print the Ø3 hole gauge; push a 3 mm dowel pin through each: the first that slips freely is your 'clearance', the last that needs a tap is your 'press'. If 3.2 slips and 3.0 presses, your printer matches the library and nothing needs changing. If it takes 3.4 to slip, set a horizontal hole compensation of +0.2 mm in the slicer (or scale holes in CAD).
- Pin gauge: the 3.0 pin should enter a 623 bearing bore with finger pressure; if only 2.9 does, external features print fat: set XY compensation −0.05. Nut gauge: the M3 nut should push into the 5.8 AF trap and not fall out of 5.6. Tongue gauge against real 2020: 5.8 slides, 6.0 binds. Pocket gauge: a 608 presses into 22.2 with a thumb and holds.
- Do this once per printer and filament (PETG shrinks less than PLA, ABS more); write the two numbers (hole offset, XY offset) in your slicer profile. After that every STEP and STL on xemstudio.com fits as drawn, and an AI agent designing around these sheets can use the stated clearances without guessing.

gauge  what it tests  pass condition
hole 2.8–3.6  Ø3 pivots / M3 clearance  3.0 press, 3.2 slip, 3.4 clearance
hole 4.8–5.6  Ø5 shafts  5.0 press, 5.2 slip
hole 7.8–8.6  Ø8 shafts  8.0 press, 8.2 slip
pin 2.8–3.2 / 4.8–5.2  printed pins into bearings  3.0 / 5.0 enters finger-tight
nut trap M3/M4  captive nuts  5.8 / 7.2 AF snug
tongue 5.6–6.0  T-slot brackets  5.8 slides in 2020
pocket 10/16/22  623 / 625 / 608 pockets  +0.2 thumb press

Files elsewhere (not hosted by Xem Studio; license as stated by the publisher):
- Wikipedia: Engineering tolerance — web — CC BY-SA 4.0 (text) — https://en.wikipedia.org/wiki/Engineering_tolerance
- Prusa: Knowledge base: XY size compensation — web — Prusa KB [verify license at link] — https://help.prusa3d.com/article/xy-size-compensation_125045
- Long Earth Society: Engine and rig builds — web, video — LES site — https://longearthsociety.com/engineering/

Free files (CC BY 4.0, Xem Studio; STEP + STL, 8 parts): https://xemstudio.com/files/hardware/printer-calibration-coupons/index.json
API: https://xemstudio.com/api/geometry?object=printer-calibration-coupons