What happens when you hob teeth on the wrong pitch diameter?

[Garwood]

I need to cut 60 sensor target teeth into a 2.7" blank (lots of them). I'd rather not tie up a mill and indexer just doing this- I have a Hobber!

I'd like to use a cheap, off the shelf hob. The teeth are too small on Mod 1 or 24DP. Mod 1.25 or 20DP don't work out. 22DP is pretty darn close though.

I get 2.8181" outside diameter, 2.6135" for 22DP 60 teeth. 22DP hubs don't look hard to get. What would the teeth look like if I moved that hob in to cut the same teeth in a 2.7" blank?

Would it leave little slivers of teeth or would they still look like gear teeth?

I might be able to get away with 59 teeth which would be 2.7726"

Again, not making gear teeth. Just need teeth-shaped targets for a sensor to read. I'll be milling 2 teeth off of a 60 tooth wheel to make it a 60-2 and I can probably fudge a 59 tooth wheel to work as well. I can't do a 58 tooth wheel. The ECM has to see the missing tooth pulse.

 

[3t3d]

Does a gear tooth shape (pointy) give as strong a signal as perhaps a Spline shape?
Seems like a square tooth profile might give the best signal.
IIRC you were already chasing signal strength issues.

 

[Garwood]

Does a gear tooth shape (pointy) give as strong a signal as perhaps a Spline shape?
Seems like a square tooth profile might give the best signal.
IIRC you were already chasing signal strength issues.

The sensor I settled on puts out a very strong voltage on a 2.7" target. On a 3.25" target the voltage is actually too high, around 60 volts, and the ecm doest read it.

I think a rounded tooth helps somewhat. The gap is ideally wider than the tooth.

 

[Mud]

The involute gets more slender, taller and more narrow at the bottom, looks like a lesser pressure angle. sort of resembles a 14.5° compared to a 20° PA. That's not the correct terminaology but the best description I have tonight. A larger pitch circle makes the gears fatter at the bottom. I think the correct terminology is profile shift when this is done. If you have any gear generation software like Gearotic it's easy to show.

They still look like gear teeth and they roll together OK.

 

[Garwood]

Gearotic? Kinky!

 

[Jashley73]

Gearotic? Kinky!

Whatever grinds your gears mate...

 

[3t3d]

Gearotic? Kinky!

Try calling the adult toy store, ask if they know how to use a circumflex... ô