# Printed pin gauges 2.8–3.2 and 4.8–5.2 mm

> How much over size do printed pins come out?

- Category: Stirling engines › Generators & instruments
- Kind: Hardware
- Basis: Pins stepped around Ø3 and Ø5 in 0.1 mm steps, tested in the bore of a 623 (Ø3) or 625 (Ø5) bearing
- Page: https://xemstudio.com/objects/pin-gauges/ · JSON: https://xemstudio.com/api/geometry?object=pin-gauges · Plain text: https://xemstudio.com/objects/pin-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 66 × 16 × 3 mm base with five pins 12 mm tall, 0.3 mm chamfered tips: Ø2.8, 2.9, 3.0, 3.1, 3.2 or Ø4.8, 4.9, 5.0, 5.1, 5.2.
- Try each pin in the bore of a 623 (Ø3) or 625 (Ø5) bearing: the pin that enters finger-tight, minus 3.0 or 5.0, is the allowance for printed pins and spigots (usually negative).

## 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 | pins_mm | test_in |
|---|---|---|
| pin-gauge-2-8-to-3-2 | 2.8 / 2.9 / 3.0 / 3.1 / 3.2 | 623 bore Ø3 |
| pin-gauge-4-8-to-5-2 | 4.8 / 4.9 / 5.0 / 5.1 / 5.2 | 625 bore Ø5 |

## 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 (2 parts, CC BY 4.0, Xem Studio)

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

- pin-gauge-2-8-to-3-2: [STEP](https://xemstudio.com/files/hardware/printer-calibration-coupons/pin-gauge-2-8-to-3-2.step) · [STL](https://xemstudio.com/files/hardware/printer-calibration-coupons/pin-gauge-2-8-to-3-2.stl) — printed pin gauge 2.8–3.2: which prints to a true Ø3 hole in a bearing?
- pin-gauge-4-8-to-5-2: [STEP](https://xemstudio.com/files/hardware/printer-calibration-coupons/pin-gauge-4-8-to-5-2.step) · [STL](https://xemstudio.com/files/hardware/printer-calibration-coupons/pin-gauge-4-8-to-5-2.stl) — printed pin gauge 4.8–5.2 (625 bearing bore test)

## How it fits

### Connects to
- [Ball bearings, 683 to 6210 and flanged F6xx (ISO 15)](https://xemstudio.com/objects/ball-bearings-metric/): pins tried in the Ø3 / Ø5 bore of a 623 / 625

### Also needed
- [Hole gauges for Ø3, Ø5 and Ø8 (0.1 mm steps)](https://xemstudio.com/objects/hole-gauges/): the matching inside-diameter test

## Questions

**Why do printed pins come out over size?**

Outside features come out fat for the same reasons holes come out small; the pin gauge measures the outside error.

**How do I read the pin gauge?**

The pin that enters a true Ø3 or Ø5 bearing bore finger-tight, minus the nominal, is your pin allowance.

## Fits with

- [Hole gauges for Ø3, Ø5 and Ø8 (0.1 mm steps)](https://xemstudio.com/objects/hole-gauges/)
- [Bearing pocket gauge for 623, 625 and 608 (Ø10 / Ø16 / Ø22, +0 / +0.2 / +0.4)](https://xemstudio.com/objects/bearing-pocket-gauge/)
- [Ball bearings, 683 to 6210 and flanged F6xx (ISO 15)](https://xemstudio.com/objects/ball-bearings-metric/)