Gear Cutting Help

[SteveM]

Have removed the cross slide from my lathe and the shaft from the hand wheel to acme screw is a 10 tooth pattern extremely worn. I've looked at involute gear cutters but the largest, #8, specs for 12-13 splines. Have looked long enough to be thoroughly confused so hoping someone can shed some light?

 

[swatson144]

Now there are 2 of us, confused that is . Are we talking splines? Is #8 referring to 8DP? What Pressure angle?
Sorry to do this but please have a look at https://www.bostongear.com/pdf/gear_theory.pdf
If it is metric it gets easier.
Boston gear may have a blank for you to bore and key.

Steve

 

[SteveM]

Thanks for the reply Steve. Using the information at boston gear the OD of the shaft(spur gear) in question is 1.175, very close to 30mm. There are 10 splines. Using the formula P = N+2/D(Outside Diameter) = 10.2? It does say the number is an approximation? When I look at Involute Gear Cutters #6 = 17-20 teeth and #8 = 12-13 teeth. I believe we're dealing with 14.5 deg PA. Would I be correct in using #6 cutter or am I still wandering in the wilderness? Thanks again for your help, Steve M.

 

[4GSR]

Involute gear cutters were never designed to cut splines. But if by luck you find a cutter that matches very close to the spline flute that needs to be cut, go for it!

Ken

Can you post a picture of the part or parts in question? You maybe talking about a pinion gear here, not a spline.

 

[SteveM]

It's actually a spur gear. Can't attach picture right now. Tech challenged and dead batteries

 

[4GSR]

Dummy me, I should have read your first post again and again. It's all there.

You should be safe using the 12-13 cutter no. 8 without issues. The tooth profile will look funny when done. Ideally, the pinion needs to be cut with a gear hobber so you get the proper generated tooth profile. Ken

 

[joshua43214]

Thanks for the reply Steve. Using the information at boston gear the OD of the shaft(spur gear) in question is 1.175, very close to 30mm. There are 10 splines. Using the formula P = N+2/D(Outside Diameter) = 10.2? It does say the number is an approximation? When I look at Involute Gear Cutters #6 = 17-20 teeth and #8 = 12-13 teeth. I believe we're dealing with 14.5 deg PA. Would I be correct in using #6 cutter or am I still wandering in the wilderness? Thanks again for your help, Steve M.

Can you please help us all get on the same page.

Splines go on a splined shaft. They are not part of gears and they are never driven like a gear.
A gear has three common names: "gear," "wheel," and "pinion." Pinions are small gears, and wheels are large gears. The teeth on a gear are called "teeth," or more properly "leaves."
There are three key things used to size and cut a gear: the pitch diameter, the circular pitch, and the pressure angle.

I think you are getting little response because many of us can not decide if you are talking about a splined shaft or a gear.
I know it sounds like I am being fussy or definitions, but there are some extremely knowledgeable people here that will be slow to give a good detailed reply if they think it might be for something other than what they think.
This is why pics are so important. It lets us see what you are trying to do.

 

[swatson144]

Hello Steve, What lathe is it? If it is a Grizzly or other import you are likely back to metric gears even if it is a standard lathe. They are in modulus and tooth count (ie 10 to rack) don't matter.

Steve