# Hole gauges for Ø3, Ø5 and Ø8 (0.1 mm steps)

> How do I find the hole allowance my 3D printer needs for parts drawn at exact size?

- Category: Stirling engines › Generators & instruments
- Kind: Hardware
- Basis: Holes stepped around the Ø3, Ø5 and Ø8 nominals in 0.1 mm (plus one 0.2 mm) steps; every file on the site is drawn at exact size
- Page: https://xemstudio.com/objects/hole-gauges/ · JSON: https://xemstudio.com/api/geometry?object=hole-gauges · Plain text: https://xemstudio.com/objects/hole-gauges/sheet.txt
- License: dimension sheet CC BY 4.0 (Xem Studio); linked files under their publishers' licenses

**Exact dimensions.** Every file is drawn at true size with no printing tolerance. The holes and pins that meet another part are listed below under Mating features, with the fit each joint needs; open those by your printer's or process's clearance before making the part.

## Notes

- Every file on this site is drawn at exact size with no printing allowance; this gauge steps through sizes around the nominal so you can measure the allowance your process needs for one fit class, then apply it only to the features each object lists under Mating features.
- Each gauge is a 118 × 24 × 5 mm plate with eight through holes on 14 mm pitch and the size engraved under each: 2.8, 2.9, 3.0, 3.1, 3.2, 3.3, 3.4, 3.6; 4.8–5.4 and 5.6; 7.8–8.4 and 8.6.
- Push a true pin or shaft into each hole: the smallest it presses into and stays is your press size, the smallest it slides through by hand your slide size, the smallest it turns freely in your run size.
- Each of those minus the nominal is your allowance for that fit class; for example a Ø3 pin that presses into 3.1 and turns freely in 3.3 gives +0.1 press and +0.3 run.

## Mating features (exact size; open press / slide / run / socket by your process clearance, leave designed and clamp as drawn)

| feature | exact | mates with | fit | files |
|---|---|---|---|---|
| gauge sizes | stepped around nominal | the true pin, nut, bearing or extrusion slot being tested | designed | all |

## Sizes

| gauge | sizes_mm | nominal_mm |
|---|---|---|
| hole-gauge-m3-2-8-to-3-6 | 2.8–3.4, 3.6 | 3 |
| hole-gauge-m5-4-8-to-5-6 | 4.8–5.4, 5.6 | 5 |
| hole-gauge-m8-7-8-to-8-6 | 7.8–8.4, 8.6 | 8 |

## Where the files are

- Wikipedia: [Engineering tolerance](https://en.wikipedia.org/wiki/Engineering_tolerance) — web — CC BY-SA 4.0 (text)
- Prusa: [Knowledge base: XY size compensation](https://help.prusa3d.com/article/xy-size-compensation_125045) — web — Prusa KB (verify at link)
- Long Earth Society: [Engine and rig builds](https://longearthsociety.com/engineering/) — web, video — LES site

## Free STEP/STL (3 parts, CC BY 4.0, Xem Studio)

Index: https://xemstudio.com/files/hardware/hole-gauges/index.json

- hole-gauge-m3-2-8-to-3-6: [STEP](https://xemstudio.com/files/hardware/printer-calibration-coupons/hole-gauge-m3-2-8-to-3-6.step) · [STL](https://xemstudio.com/files/hardware/printer-calibration-coupons/hole-gauge-m3-2-8-to-3-6.stl) — hole gauge for Ø3 pins/screws: 2.8–3.6 in 0.1 steps (find press, slip and clearance)
- hole-gauge-m5-4-8-to-5-6: [STEP](https://xemstudio.com/files/hardware/printer-calibration-coupons/hole-gauge-m5-4-8-to-5-6.step) · [STL](https://xemstudio.com/files/hardware/printer-calibration-coupons/hole-gauge-m5-4-8-to-5-6.stl) — hole gauge for Ø5 shafts: 4.8–5.6
- hole-gauge-m8-7-8-to-8-6: [STEP](https://xemstudio.com/files/hardware/printer-calibration-coupons/hole-gauge-m8-7-8-to-8-6.step) · [STL](https://xemstudio.com/files/hardware/printer-calibration-coupons/hole-gauge-m8-7-8-to-8-6.stl) — hole gauge for Ø8 shafts: 7.8–8.6

## How it fits

### Connects to
- [Dowel pins, 2–6 mm (ISO 2338 / DIN 6325)](https://xemstudio.com/objects/dowel-pins-metric/): a true Ø3 / Ø5 / Ø8 pin pushed into each hole

### Also needed
- [Printed pin gauges 2.8–3.2 and 4.8–5.2 mm](https://xemstudio.com/objects/pin-gauges/): the matching outside-diameter test
- [Bearing pocket gauge for 623, 625 and 608 (Ø10 / Ø16 / Ø22, +0 / +0.2 / +0.4)](https://xemstudio.com/objects/bearing-pocket-gauge/): the same test for bearing pockets

## Questions

**My holes print too small; what do I change?**

Find the gauge hole a true pin presses into and the one it turns freely in; the differences from nominal are your press and run allowances, applied only to the listed mating features.

**What tolerance do the files on this site include?**

None. A hole for a Ø3 pin is 3.000; these gauges measure the allowance your process needs.

## Fits with

- [Printed pin gauges 2.8–3.2 and 4.8–5.2 mm](https://xemstudio.com/objects/pin-gauges/)
- [Nut-trap gauge: M3 5.5 / 5.7 / 5.9 AF and M4 7.0 / 7.2 / 7.4 AF](https://xemstudio.com/objects/nut-trap-gauge/)
- [Bearing pocket gauge for 623, 625 and 608 (Ø10 / Ø16 / Ø22, +0 / +0.2 / +0.4)](https://xemstudio.com/objects/bearing-pocket-gauge/)
- [T-slot tongue gauge 5.6 / 5.8 / 6.0 mm (6 mm slot)](https://xemstudio.com/objects/extrusion-tongue-gauge/)
- [Dowel pins, 2–6 mm (ISO 2338 / DIN 6325)](https://xemstudio.com/objects/dowel-pins-metric/)