10 tooth gear, involute cutter

[kcmillin]

I cannot find an involute gear cutter for 48dp gears. I have a cutter that cuts 12 and 13 tooth gears, but nothing smaller. Is there such a thing as a #9 gear cutter in 48dp.

I am trying to design a gear style water pump and would like a 10 tooth gear, to keep things small.

For this application would It be alright using the 12 tooth cutter to make the 10 tooth gears I need? When I look at a #1 and a #8 gear cutter side by side I can barley see the difference, the difference between two consecutive numbers is almost completely unnoticeable.

Kel

 

[tel]

Give it a shot with the #8 and report back Kel. I've never heard tell of a #9 - not that that means much.

 

[Mainer]

With only 10 teeth you'll get serious undercutting of the teeth. I'm not sure how the #8 cutter will handle that. Just have to try it. The tooth form you get will be more incorrect than it would be if the number of teeth were in the range of the cutter. How much that matters will likely depend a lot on how fast you run it.

If 'twere me I think I'd opt for a couple more teeth...but see what happens with 10. It might work okay. All the gears that are made with cutters are approximations, anyway, except perhaps one tooth count within the range of each cutter.

 

[gbritnell]

Hi Kel,
I don't know what they cut their gears with but Stock Drive Products stocks 48 DP. gears down to 7 teeth. If you can't use a stock gear then the next thing would be to make a hob and cut what you need. When I was building my V-twin I ran into the same thing with the gears for my oil pump, I couldn't get an involute small enough to cut what I needed so I just purchased them. Here's the link for SDP.
https://sdp-si.com/eStore/
gbritnell

 

[John S]

Depends a lot on the Pressure Angle.

This is two 48DP gears with 10 teeth at 20 degrees PA.

and this is the same setup but at 14.5 degrees PA.

John S.