Measuring pitch

[69Z/28-Nut]

B

Yes, but written more correctly: (N + 2) then / by Dp. Or (N + 2) / Dp. Order of operation is the most common cause of people not liking math.

Try this chart for all your calculations.

View attachment 279727

Wish this chart were larger, at my age I can no longer see small print.

 

[BROCKWOOD]

I can do that when I get home tomorrow morning Mr Z Man.

 

[BROCKWOOD]

PM sent Mr Z Man. Hobby Machinist has this resizing gizmo that automatically makes my info too small no matter how large or clear it was when I uploaded it. Here is a pic I made for diameter.



Perhaps this pic will be more useful.

 

[Bob Korves]

PM sent Mr Z Man. Hobby Machinist has this resizing gizmo that automatically makes my info too small no matter how large or clear it was when I uploaded it. Here is a pic I made for diameter.

View attachment 281079

Perhaps this pic will be more useful.

The original poster is asking for the diametral pitch of the gear, not for the diameter.

 

[BROCKWOOD]

OK then solve for P.



That example worked out a little too smoothly!

GIVEN: N = 59, Do = 7 (Just random numbers)

(59 + 2) / 7 = 8.714~

That's messy. If this were an existing gear in a drivetrain: I'd be checking the mating gear, my math, the tooth pictures in Machinery's Handbook & the Black Book.

If I had to have 59 teeth in order to maintain a certain ratio with the next gear, I would check diameter with P = 8 & with P = 9 & adjust the rest of the design to fit.

 

[benmychree]

Easiest is to just purchase a set of gear pitch gaged, made from stamped steel; they have 14 1/2 deg on one side and 20 deg on the other and are not expensive,

 

[chips&more]

Easiest is to just purchase a set of gear pitch gaged, made from stamped steel; they have 14 1/2 deg on one side and 20 deg on the other and are not expensive,

For what they are. Just stamped metal. They can be very expensive. I would instead just do a search on the net for “gear tooth profile”. You will get enough head spinning info there for free. Even pics of 14 1/2° & 20° examples…Dave
https://www.amazon.com/Fowler-Involute-Gear-Tooth-Holder/dp/B00B5KQIKK

 

[benmychree]

I am quite sure that they are available for much less than that ------ Amazon, instant gratification at a price!

 

[chips&more]

Yeah, on fleabay from India. It amazes me on how some people value their dollar.

https://www.ebay.com/itm/Gear-Tooth...=item2abd5b8d72:g:gncAAOSwYwhba8nq:rk:16:pf:0