How Would I Machine this CAD designed Ratchet

[JasonB]

On JasonB Said:

Any reason why the pawl can’t be rotated 90deg and act on teeth on the side of the wheel?

Yes, that would be mechanically very much better but you would need a light spring instead of relying on gravity (assuming the axis of the wheel is gong to be vertical). It would avoid the end of the pawl having to slide on the wheel as it pushes.

[Nigel Graham 2Participant @nigelgraham2]

Just a daft question….

Do the teeth really need be that shape? Would something like gear-teeth with straight flanks work?

If so and the number is even you can simply cut the gullets straight across the diameter and add the core as a separate piece, or use a slot-drill if semicircular ends into the central boss don’t matter.

What made me ask?

The shaping-machine!

The feed-ratchet on my Drummond hand-shaper resembles a pinion, but seems to have straight-flank teeth. The pawl is a rigid rod that reciprocates within a guide oscillating about the feed-screw axis. The tip is profiled to ramp it out of the gullet.

So for your crown-wheel pattern, could the pawl be L-shaped with an appropriate asymmetrical bevel, reciprocating in a block restrained by a rotary spring, but which swings to let the pawl climb on the return stroke?

No fancy teeth-shape, no unusual cutters or complicated machine setting; though if end-milled, I am not sure if offsets are needed for making the flanks chordal rather than radial.

[Author]

Posts