myWerkzeug.de › CNC.myWerkzeug.de › Templates › Technology and experiments
CNC template · Technology and experiments
Scotch yoke for sine motion
A crank pin slides in a slot and pushes a slider back and forth between guide strips, exactly following a sine. Compare with the crank drive: here without a connecting rod. Crank radius adjustable.
- Size
- 370 × 370 mm, 6 mm thick
- Material
- Plywood
- Difficulty
- Intermediate
- Milling time
- approx. 35 min
- Bits
- V-bit 60°, End mill Ø 3.175 mm
- Customise
- Size, text and details adjustable with sliders
- With a laser
- diode laser from about 10 W (cuts 6 mm)
Try it without an account · carve with Chrome or Edge · no installation
Build instructions
Materials and accessories
| Qty | Part |
|---|---|
| 1 | Beech dowel rod 8 mm |
| 1 | Wood glue (water-resistant D3) |
Also: sandpaper (grit 120 and 240), a utility knife or fine saw and, for joints, a rubber mallet.
Carving and finishing
- Clamp the workpiece flat on the spoilboard or secure it with double-sided tape, and set the origin as shown in the carving assistant.
- Engrave the sine scale, mill axle holes and slot, then cut out base, crank disc, slider and the four guide strips.
- Free the parts at the holding tabs with a utility knife or fine saw and sand the tab remains flush.
- Before gluing, dry-fit everything. If a joint is too tight, increase the clearance by 0.05 mm and carve the part again; if it wobbles, reduce it.
Assembly and final touches
- Glue the guide strips together in pairs and glue both double strips onto the engraved fields of the base; the slider glides between them above the crank disc.
- Glue a dowel into the base as shaft, put the crank disc on loosely and glue in a crank pin tightly that sticks up through the slider's slot.
- Turn and watch against the scale: the slider moves exactly like a sine, fastest in the middle.
How to carve this template
- OpenOpen the template in the app and adjust size and text if you like.
- CheckLook at it in 3D, check run time and warnings.
- Set upThe carve wizard guides you through material, clamping, bit and zero point.
- CarvePress start; the app drives your Grbl router directly over USB.
