Sourcing Worm and Wheel Gear Arrangement

[HopperParticipant @hopper]

David, you might be able to source suitable gears from an old motorbike speedo drive or tacho drive.

I know that 1970s Harleys used a front wheel driven speedo with a reduction gearbox that slipped over the front axle, which was about 16mm diameter. And they were a 2:1 ratio.

Old Smiths tachometer drive off 1950s British motorbikes also uses a set of skew gears that might suit and would be a little smaller. (those old drives are getting kind of expensive though.)

It might be worth a visit to your local motorbike wreckers to see if they have any similar units off more common Japanese bikes that may be useful.

[HopperParticipant @hopper]

I think what you want though are more commonly called skew gears, and SDP seems to call them screw gears, see link

**LINK**

[JasonBModerator @jasonb]

Our American friends who supply casting sets for side shaft engines are nice enough to provide the gears separately such as Debolt, there is another when I think of it.

You could also ask Kurt at Hemmingway if he will sell a set of Wyvern ones or Reeves for a set of Centaur gears.

All these will be 2:1 ratio and suite a thicker crankshaft than timing gear pivot

[Martin ConnellyParticipant @martinconnelly55370]

JasonB, you are of course correct about 0.707 and 1.414 and the square root of 2, I should have said 0.707 is the inverse of square root of 2. More haste more mistakes applies to everything.

Martin

[Ian S CParticipant @iansc]

Got #4527 ME today, Allan Brothers Lampless Oil Engine pt 8, this is about the timing gears for this engine.

Ian S C

[David CambridgeParticipant @davidcambridge45658]

Thank you everybody. I’ve just spoken to a very helpful chap at Hemmingway and he can supply me a pair.

David

[Author]

Posts