# CheapCAD Tools

> Browser-based parametric CAD generators that make complete, printable or machinable parts: timing belt pulleys today, sprockets and gears coming. Designing is free; STL, STEP, DXF and SVG downloads cost tokens.

## Use from an AI app

- MCP connector (streamable HTTP, OAuth sign-in): https://cheapcadtools.com/mcp. Tools: list_apps, describe, check (dimensions, standards warnings, Auto-fix), quote, export (a download link), balance.
- [How to connect](https://cheapcadtools.com/ai/): Claude, Claude Code, ChatGPT, Cursor, VS Code.
- HTTP API: GET https://cheapcadtools.com/tools/pulleys/api/v1/describe lists every parameter; POST check, quote and files take {"params": {...}}. Sizes are mm.

## Tools

- [Timing Pulley Generator](https://cheapcadtools.com/timing-pulley-generator/) (Live): GT2, HTD, T5, XL and 30+ more belt profiles. Hubs, set screws, spline and hex bores, spokes and flanges, as a single pulley or a two-pulley drive.
- [Sprocket Designer](https://cheapcadtools.com/sprocket-generator/) (Coming soon): Roller-chain sprockets for ANSI, ISO 606 and bicycle chains — single or multi-strand, with hubs, bores and spokes, as a two-sprocket drive.
- [Gear Designer](https://cheapcadtools.com/gear-generator/) (Coming soon): Involute spur, helical and herringbone gears by module or diametral pitch — single gears, pairs, internal rings and racks, checked against DIN 3960.
- [E-Box Designer](https://cheapcadtools.com/e-box-designer/) (Work in progress): parametric 3D-printed enclosures for electronics: draw the box, place the boards, cut the holes, print it.

## Samples, with the prompt that builds each one

- [GT2 20T & 30T, 5 mm D-Flat Stepper Pulley](https://cheapcadtools.com/samples/gt2-20t-30t-stepper-pulleys-d-flat-captured-nut/): The 3D-printer classic done properly: a D-flat that keys onto the motor shaft, a set screw that bites into a captured nut instead of the plastic, and a 30-tooth partner held by two heat-set inserts.
  Prompt: Using the CheapCAD Tools connector, design a two-pulley timing belt drive: GT2 belt (2 mm pitch), about 80 mm between centres. Pulley 1: 20 teeth, 5 mm bore with a D-flat 0.5 mm deep, a hub 16 mm across and 8 mm tall with one M3 set screw in a captured nut, and printed flanges with the top flange printed in place. Pulley 2: 30 teeth, 8 mm bore, a hub 20 mm across and 8 mm tall with two M3 set screws in heat-set inserts. Check the design, apply any Auto-fix it suggests, then export both pulleys as STL and give me the download link.
- [FRC HTD 5M 24T & 36T, ½" Rounded Hex](https://cheapcadtools.com/samples/frc-htd-5m-pulleys-rounded-hex-bore/): Ready for an FRC robot: the bore fits REV ½" rounded hex shaft, with SH-50 retaining-ring grooves on both faces and a splined washer under each ring so nothing walks along the shaft.
  Prompt: Using the CheapCAD Tools connector, design a two-pulley timing belt drive: HTD 5M belt, 24 and 36 teeth, about 160 mm between centres. Bore both pulleys for ½" rounded hex shaft (REV style: 12.7 mm across flats, 13.75 mm across corners) with inch retaining-ring grooves on both faces and a splined washer under each ring, and give each a hub 30 mm across and 8 mm tall. The 36-tooth pulley gets printed flanges, with its top flange printed as a separate part. Check the design, apply any Auto-fix it suggests, then export both pulleys as STL and give me the download link.
- [HTD 5M 20T & 30T, ISO Keyways & Metal Flanges](https://cheapcadtools.com/samples/htd-5m-20t-30t-keyway-metal-flanges/): Built like a machined part: ISO 773 keyways sized to 12 mm and 20 mm shafts, M5 set screws to lock them, and flanges drawn as bent metal plates instead of printed rims.
  Prompt: Using the CheapCAD Tools connector, design a two-pulley timing belt drive: HTD 5M belt, about 150 mm between centres, M5 set screws in both hubs. Pulley 1: 20 teeth, 12 mm bore with a 4 mm wide, 2 mm deep keyway, a hub 26 mm across and 10 mm tall, and flanges drawn as metal plates. Pulley 2: 30 teeth, 20 mm bore with a 6 mm wide, 3.1 mm deep keyway, a hub 34 mm across and 10 mm tall. Check the design, apply any Auto-fix it suggests, then export both pulleys as STL and give me the download link.
- [GT2 40T & 60T, Spoked Thin-Web Pulleys](https://cheapcadtools.com/samples/gt2-40t-60t-spoked-lightweight-pulleys/): Big printed pulleys don't need to be solid: five and six spokes on a thin centre web cut plastic and print time, while the toothed rim stays full width for the belt.
  Prompt: Using the CheapCAD Tools connector, design a two-pulley timing belt drive: GT2 belt (2 mm pitch), about 120 mm between centres, 8 mm bores, and on each pulley a hub 18 mm across and 7 mm tall with an M3 set screw. Lighten both with spokes on a thin web 4 mm tall, a 3 mm rim under the teeth and an 18 mm spoke hub: 5 spokes on pulley 1 (40 teeth) and 6 spokes on pulley 2 (60 teeth). Pulley 2 also gets printed flanges, with the top flange printed in place. Check the design, apply any Auto-fix it suggests, then export both pulleys as STL and give me the download link.
- [GT2 16T & 24T, Zero-Backlash Fit](https://cheapcadtools.com/samples/gt2-16t-24t-zero-backlash-pulleys/): Tuned for positioning rather than power: tight tooth clearance, no backlash allowance and 0.1 mm of print compensation, so the printed teeth hold the belt without slop.
  Prompt: Using the CheapCAD Tools connector, design a two-pulley timing belt drive: GT2 belt (2 mm pitch), 16 and 24 teeth, about 60 mm between centres, tuned for positioning: tight tooth clearance, no backlash allowance and 0.1 mm of print compensation on both. Each has a 5 mm bore and a hub 14 mm across and 7 mm tall with an M3 set screw in a captured nut. Pulley 1 gets printed flanges, with the top flange printed in place. Check the design, apply any Auto-fix it suggests, then export both pulleys as STL and give me the download link.
- [HTD 3M 24T & 36T, ISO 4156 Involute Splines](https://cheapcadtools.com/samples/htd-3m-24t-36t-involute-spline-bore/): Splined like a gearbox shaft: ISO 4156 involute splines in module 1, with a flat root at 30° on the small pulley and a fillet root at 37.5° on the large one.
  Prompt: Using the CheapCAD Tools connector, design a two-pulley timing belt drive: HTD 3M belt, about 110 mm between centres, with ISO 4156 involute splined bores in module 1. Pulley 1: 24 teeth, a 9-tooth spline at 30° with a flat root, a hub 20 mm across and 7 mm tall, and printed flanges with the top flange printed in place on breakaway print supports. Pulley 2: 36 teeth, a 16-tooth spline at 37.5° with a fillet root, a hub 27 mm across and 7 mm tall. Check the design, apply any Auto-fix it suggests, then export both pulleys as STL and give me the download link.
- [HTD 8M 24T & 36T, ISO 14 Splined Bores](https://cheapcadtools.com/samples/htd-8m-24t-36t-iso-14-spline-bore/): Heavy-duty HTD 8M on splined shafts: straight-sided ISO 14 splines carry torque no set screw could, and the 36-tooth pulley is spoked around its spline hub.
  Prompt: Using the CheapCAD Tools connector, design a two-pulley timing belt drive: HTD 8M belt, about 250 mm between centres, with straight-sided ISO 14 splined bores. Pulley 1: 24 teeth, a 6 × 23 × 26 spline (6 mm spline width), a hub 40 mm across and 10 mm tall. Pulley 2: 36 teeth, a 6 × 28 × 32 spline (7 mm spline width), a hub 48 mm across and 10 mm tall, 6 spokes around a 48 mm spoke hub with a 4.1 mm rim under the teeth, and flanges drawn as metal plates reaching 4.2 mm past the teeth. Check the design, apply any Auto-fix it suggests, then export both pulleys as STL and give me the download link.
- [GT3 20T & 30T, Flanges Printed in Place](https://cheapcadtools.com/samples/gt3-20t-30t-flanges-printed-in-place/): One print, no glue: both flanges print in place, the top one on breakaway supports sized for a 0.4 mm nozzle, so each pulley comes off the bed finished.
  Prompt: Using the CheapCAD Tools connector, design a two-pulley timing belt drive: GT3 belt (3 mm pitch), 20 and 30 teeth, about 90 mm between centres. Pulley 1 has a 6 mm bore and a hub 16 mm across and 7 mm tall; pulley 2 an 8 mm bore and a hub 18 mm across and 7 mm tall; an M3 set screw in each hub. Both get printed flanges with the top flange printed in place, on breakaway print supports sized for a 0.4 mm nozzle. Check the design, apply any Auto-fix it suggests, then export both pulleys as STL and give me the download link.
- [AT5 24T & 36T, Heat-Set Insert Set Screws](https://cheapcadtools.com/samples/at5-24t-36t-heat-set-insert-pulleys/): For a linear axis that gets adjusted often: AT5's stiff belt, with M4 set screws running in heat-set inserts so the threads survive, and a spoked 36-tooth pulley.
  Prompt: Using the CheapCAD Tools connector, design a two-pulley timing belt drive: AT5 belt, about 140 mm between centres, M4 set screws in heat-set inserts on both hubs. Pulley 1: 24 teeth, 8 mm bore, a hub 22 mm across and 9 mm tall. Pulley 2: 36 teeth, 10 mm bore, a hub 24 mm across and 9 mm tall, 5 spokes around a 24 mm spoke hub with a 5 mm rim under the teeth, and printed flanges whose top flange is a separate part held on by 12 gluing nubs. Check the design, apply any Auto-fix it suggests, then export both pulleys as STL and give me the download link.
- [T5 20T & 30T, 16 mm Wide Belt](https://cheapcadtools.com/samples/t5-20t-30t-16mm-wide-belt-pulleys/): More belt for more load: a 16 mm T5 belt with the face widened to suit, on D-flat shafts with an M4 set screw in each hub.
  Prompt: Using the CheapCAD Tools connector, design a two-pulley timing belt drive: T5 belt 16 mm wide, about 120 mm between centres, one M4 set screw in each hub. Pulley 1: 20 teeth, 8 mm bore with a D-flat 0.5 mm deep, a hub 20 mm across and 9 mm tall, and printed flanges with the top flange printed in place. Pulley 2: 30 teeth, 10 mm bore with a D-flat 0.8 mm deep, a hub 24 mm across and 9 mm tall. Check the design, apply any Auto-fix it suggests, then export both pulleys as STL and give me the download link.
- [XL 20T & 30T, ¼" & ⅜" Bores, Inch Set Screws](https://cheapcadtools.com/samples/xl-20t-30t-imperial-pulleys-inch-set-screws/): Imperial down to the hardware: an XL belt, ¼" and ⅜" shafts, and #8-32 and #10-24 set screws in captured nuts.
  Prompt: Using the CheapCAD Tools connector, design a two-pulley timing belt drive: XL belt, about 120 mm between centres, set screws in captured nuts. Pulley 1: 20 teeth, ¼" bore, a hub 18 mm across and 9 mm tall with a #8-32 set screw, and printed flanges with the top flange printed as a separate part. Pulley 2: 30 teeth, ⅜" bore, a hub 22 mm across and 10 mm tall with a #10-24 set screw. Check the design, apply any Auto-fix it suggests, then export both pulleys as STL and give me the download link.
- [L 20T & 30T, ½" & ¾" Keyed Bores](https://cheapcadtools.com/samples/l-20t-30t-keyed-inch-bore-pulleys/): The ⅜" L pitch for heavier inch-sized machines: ½" and ¾" bores with ⅛" and 3/16" keyways, and a 1/4-20 set screw on the larger hub.
  Prompt: Using the CheapCAD Tools connector, design a two-pulley timing belt drive: L belt (⅜" pitch), about 200 mm between centres. Pulley 1: 20 teeth, ½" bore with a ⅛" wide, 1.6 mm deep keyway, a hub 30 mm across and 12 mm tall with a #10-24 set screw. Pulley 2: 30 teeth, ¾" bore with a 3/16" wide, 2.4 mm deep keyway, a hub 38 mm across and 12.7 mm tall with a 1/4-20 set screw, and flanges drawn as metal plates. Check the design, apply any Auto-fix it suggests, then export both pulleys as STL and give me the download link.
- [MXL 20T & 30T, Miniature with M2 Screws](https://cheapcadtools.com/samples/mxl-20t-30t-miniature-pulleys/): Small and fine-pitched: 0.08" MXL teeth on 3 mm and 4 mm shafts, held by M2 set screws in hex-shaped tapped holes.
  Prompt: Using the CheapCAD Tools connector, design a two-pulley timing belt drive: MXL belt, about 50 mm between centres, M2 set screws in hex-shaped threaded holes. Pulley 1: 20 teeth, 3 mm bore, a hub 10 mm across and 6 mm tall, and printed flanges with the top flange printed in place. Pulley 2: 30 teeth, 4 mm bore, a hub 12 mm across and 6 mm tall. Check the design, apply any Auto-fix it suggests, then export both pulleys as STL and give me the download link.
- [STD S3M 30T & 45T, Custom Tooth Fit](https://cheapcadtools.com/samples/std-s3m-30t-45t-custom-fit-pulleys/): When the presets aren't quite right for your printer: tooth clearance and backlash dialled in by hand, on the round-toothed STD S-series profile.
  Prompt: Using the CheapCAD Tools connector, design a two-pulley timing belt drive: STD S3M belt, about 110 mm between centres, with a custom tooth fit on both pulleys: 0.08 mm tooth clearance and 0.04 mm backlash. Pulley 1: 30 teeth, 6 mm bore with a D-flat 0.5 mm deep, a hub 18 mm across and 7 mm tall with an M3 set screw, and printed flanges with the top flange printed in place. Pulley 2: 45 teeth, 8 mm bore, a hub 20 mm across and 7 mm tall with an M3 set screw. Check the design, apply any Auto-fix it suggests, then export both pulleys as STL and give me the download link.
- [RPP 5M 20T & 30T, Three-Spoke Web](https://cheapcadtools.com/samples/rpp-5m-20t-30t-three-spoke-pulleys/): RPP's parabolic teeth around an open three-spoke web, with generous fillets at both ends of every spoke.
  Prompt: Using the CheapCAD Tools connector, design a two-pulley timing belt drive: RPP 5M belt, about 150 mm between centres, an M4 set screw in each hub. Pulley 1: 20 teeth, 8 mm bore, a hub 20 mm across and 8 mm tall. Pulley 2: 30 teeth, 10 mm bore, a hub 22 mm across and 8 mm tall, 3 spokes 6 mm wide around a 22 mm spoke hub with a 3 mm rim under the teeth, a 3 mm fillet where each spoke meets the rim and 4 mm at the hub, and printed flanges with the top flange printed in place on breakaway print supports. Check the design, apply any Auto-fix it suggests, then export both pulleys as STL and give me the download link.
- [HTD 14M 24T & 36T, Industrial Size](https://cheapcadtools.com/samples/htd-14m-24t-36t-industrial-pulleys/): Industrial scale: an HTD 14M drive for a 40 mm belt, keyed 35 mm and 50 mm bores, a spoked 36-tooth pulley over 160 mm across, and metal-plate flanges.
  Prompt: Using the CheapCAD Tools connector, design a two-pulley timing belt drive: HTD 14M belt 40 mm wide, about 600 mm between centres, ISO keyways. Pulley 1: 24 teeth, 35 mm bore with a 10 mm wide, 3.6 mm deep keyway, a hub 70 mm across and 20 mm tall, and flanges drawn as metal plates reaching 7.5 mm past the teeth. Pulley 2: 36 teeth, 50 mm bore with a 14 mm wide, 4.2 mm deep keyway, a hub 80 mm across and 20 mm tall, and 6 spokes 10 mm wide around an 80 mm spoke hub with a 10 mm rim under the teeth and 6 mm fillets at both ends. Check the design, apply any Auto-fix it suggests, then export both pulleys as STL and give me the download link.

## More

- [Pricing](https://cheapcadtools.com/pricing/)
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- [Contact](https://cheapcadtools.com/contact/)