# Print-in-place: rotary dial with 24 detents (compliant arms)

> How do you 3D print a clicking rotary dial (detent knob) in one piece?

- Category: 3D printing › Print-in-place mechanisms
- Kind: Hardware
- Basis: Xem Studio design: V-notch detents, compliant arms, 45° V-groove bearing; one designed running gap of 0.40 mm
- Page: https://xemstudio.com/objects/print-in-place-detent-dial/ · JSON: https://xemstudio.com/api/geometry?object=print-in-place-detent-dial · Plain text: https://xemstudio.com/objects/print-in-place-detent-dial/sheet.txt
- License: dimension sheet CC BY 4.0 (Xem Studio); files Xem Studio Design License (free to use and sell from, not to redistribute as files: https://xemstudio.com/license/)
- Use in every chat: add https://xemstudio.com/mcp as a connector (https://xemstudio.com/use-with-ai/)

## Overall (mm)

| length | width | height |
|---|---|---|
| 80.0 | 80.0 | 25.7 |

**Exact dimensions.** True size, with no printing tolerance added.

## Notes

- 3D print in place — prints already assembled, moving, in one job. Drawn at true size with no printer tolerance added; the 0.40 mm running gaps are part of the design.
- Running gap 0.40 mm per side, 0.80 mm on diameter — part of the design, drawn as is. On the 45° faces the same 0.40 mm is measured square to the face (0.57 mm along the axis).
- Bed: flat. Frame ring and dial both on the bed; in the bottom 6 mm layer the frame bore has 24 V-notches and the dial two thin arms with 45° bumps sitting in opposite notches, 0.40 mm clear.
- Support while printing: over the arms the frame closes as a 45° cone (0.40 mm square to the bumps' top corners), then holds the dial's boss with a 45° V-ridge in a V-groove. Nothing overhangs more than 45°.
- Captured: the V-ridge in the boss's V-groove holds the dial up and down and centres it.
- Freeing it: hold the frame and turn the knob through a full turn each way.
- Motion: continuous rotation both ways with 24 detent positions (15° apart) marked on the frame top; between positions each arm bends 1.5 mm inward as its bump climbs out of a notch. At a detent the dial is free for ±1.05° (computed).

## Sizes

| key | value | what |
|---|---|---|
| gap_mm | 0.4 | running gap per side on every moving interface (radial, axial, under captured parts) — part of the design, not a tolerance |
| frame_od_mm | 80.0 |  |
| detents | 24 | positions per turn, every 15° |
| notch_depth_mm | 1.5 | 45° V notches in the frame bore Ø60 |
| arms | 2 | flexible detent arms on the dial, 180° apart |
| arm_mm | 1.6 wide × 80° of arc |  |
| arm_flex_mm | 1.5 | bump travel inward between positions |
| free_play_deg | 1.05 | rotation before a bump meets a notch flank, each way |
| knob_d_mm | 51.2 | dial boss / knob, pointer slot on top |
| axial_play_mm | 0.57 |  |
| height_mm | 25.67 | as printed |
| index_marks | 24 | on the frame top |
| mount_holes | 3 × Ø3.4 | frame |

## Where the files are

- Xem Studio: [Print-in-place mechanism design (geometry computed in the generator)](https://xemstudio.com/) — web — Xem Studio design

## Free STEP/STL (3 parts, Xem Studio Design License, Xem Studio)

Index: https://xemstudio.com/files/hardware/print-in-place-detent-dial/index.json · license: https://xemstudio.com/files/hardware/print-in-place-detent-dial/LICENSE.md

- print-in-place-detent-dial-assembly: [STEP](https://xemstudio.com/files/hardware/print-in-place-detent-dial/print-in-place-detent-dial-assembly.step) · [STL](https://xemstudio.com/files/hardware/print-in-place-detent-dial/print-in-place-detent-dial-assembly.stl) — The whole print as laid on the bed (2 bodies, already assembled); STEP keeps each moving body a separate solid
- print-in-place-detent-dial-frame: [STEP](https://xemstudio.com/files/hardware/print-in-place-detent-dial/print-in-place-detent-dial-frame.step) · [STL](https://xemstudio.com/files/hardware/print-in-place-detent-dial/print-in-place-detent-dial-frame.stl) — Frame ring Ø80 with 24 detent notches, index marks, 45° cone and V-ridge bearing, 3 × Ø3.4
- print-in-place-detent-dial-dial: [STEP](https://xemstudio.com/files/hardware/print-in-place-detent-dial/print-in-place-detent-dial-dial.step) · [STL](https://xemstudio.com/files/hardware/print-in-place-detent-dial/print-in-place-detent-dial-dial.stl) — Dial with two flexible detent arms, boss with 45° V-groove, knob with pointer slot

## Questions

**How does a print-in-place dial click?**

Two thin arms on the dial carry 45° bumps that sit in 45° notches of the frame; turning it bends the arms inward until the bumps drop into the next notches.

**How many positions?**

24, every 15°; both arms engage at once (notches 180° apart).

## Fits with

- [Print-in-place: captive wheel on a printed axle (Ø40 × 12)](https://xemstudio.com/objects/print-in-place-captive-wheel-axle/)
- [Print-in-place: barrel hinge, three knuckles, folds 180° (48.8 mm)](https://xemstudio.com/objects/print-in-place-barrel-hinge-180/)
- [Print-in-place: seven-knuckle hinge on a captive through-pin (58.4 mm)](https://xemstudio.com/objects/print-in-place-multi-knuckle-hinge/)
- [Print-in-place: captive turntable with V-ridge retention (Ø80 platter)](https://xemstudio.com/objects/print-in-place-captive-turntable/)
- [Print-in-place: linear slider on a dovetail rail with end stops (100 mm)](https://xemstudio.com/objects/print-in-place-dovetail-slider/)
- [Print-in-place: articulated chain, 6 links, 20 mm pitch](https://xemstudio.com/objects/print-in-place-articulated-chain/)
- [Print-in-place: captive ball joint, Ø24 ball, limited cone](https://xemstudio.com/objects/print-in-place-ball-joint/)