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Optical encoder disc Ø60, 30 slots, Ø5 bore
How many slots for an RPM encoder disc, and what size? · Hardware · basis: Slotted disc for a transmissive IR slot sensor (TCST2103, 3.1 mm gap): Ø60 × 1.5, 30 slots on a 48 mm circle, Ø5 bore
Long Earth Society build part. Hot-end thermocouple, cold-side DS18B20 and the flywheel RPM pickup on every LES engine. The engines
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. Mating features
- sizes
- 5 in table
Notes
- The disc is Ø60 × 1.5 mm with a Ø5 bore for a Ø5 shaft.
- It has 30 radial slots, each 2 mm wide × 6 mm long, centred on a Ø48 circle (from r 21 to r 27), 12° apart: 30 pulses per revolution.
- At 1.5 mm thick it passes through the 3.1 mm gap of a TCST2103-type IR slot sensor.
- Rpm = pulses per second × 60 / 30.
Sizes
| feature | size |
|---|---|
| disc | Ø60 × 1.5 |
| bore | Ø5 |
| slots | 30 × 2 wide × 6 radial |
| slot circle | Ø48 |
| pitch | 12° |
Mating features
Drawn at the exact size. Open press, slide, run and socket features by your process's clearance; leave designed gaps and clamp fits as drawn.
| feature | exact | mates with | fit | files |
|---|---|---|---|---|
| encoder bore | Ø5 | Ø5 shaft | slide | encoder-disc-* |
| encoder slots | 30 × 2 wide × 6 radial | IR slot sensor (3.1 gap) | designed | encoder-disc-* |
Where the files are
Other publishers' files are linked, not hosted. "verify" = check the license at the link before commercial use.
| Wikipedia | Thermocouple | web | CC BY-SA 4.0 (text) |
| Wikipedia | Hall effect sensor | web | CC BY-SA 4.0 (text) |
| Wikipedia | Dial indicator | web | CC BY-SA 4.0 (text) |
| Analog Devices | DS18B20 datasheet | Manufacturer datasheet | |
| Long Earth Society | Engine and rig builds | web, video | LES site |
Free files
★ Free files 1 parts. Generated by Xem Studio from the standard; threads are plain cylinders at major diameter. CC BY 4.0. index.json
| encoder-disc-30-slots-60mm | optical encoder disc Ø60 × 1.5, 30 slots 2 wide × 6 radial on a 48 mm circle, Ø5 bore (for an IR slot sensor) | STEP · STL |
Plain text: sheet.txt · JSON: /api/geometry?object=encoder-disc
How it fits
Goes in or on
Metric shafts Ø3 to Ø10 with D-flats and clip…Ø5 bore on a Ø5 shaft (slide)Alternatives
Hall sensor mount for TO-92Smagnetic pickup instead of opticalYou might also need
Questions
How do I measure RPM with an encoder disc?
Count slot pulses from the IR slot sensor: rpm = pulses per second × 60 / 30 for this 30-slot disc.
Will a 1.5 mm disc fit an IR slot sensor?
Yes; the TCST2103 gap is 3.1 mm.