gear pressure angle 1

[multiproducts]

We are suspect of the pressure angle we get from our gear suppliers. Documentation has been lost, etc. What is the best way to measure the pressure angle? We have an optical comparator but not a CMM. I have tried to measure the pressure angle on our comaparator but get values like 16 deg. when it should be 20 or 14.5 deg.

Thanks

 

[gearcutter]

If you look at my previous posts you will see that I have already explained how to do this.
Remember that you are not measuring the PA, as you say in your last post. What you're measuring is the Base Pitch.

 

[gearcutter]

I can send you, or any one else for that matter, base pitch charts, this allows for quicker gear identification as there are no calculations needed. You can contact me via: brunkeng at bigpond com , where there is a dot between the words bigpond and com, no spaces between any words and the word "at" is replaced with the usual character used in sending emails. I can't post the actual address as this forum won't allow it.

 

[gearcutter]

Sorry, that's my old address. The new one is: brunkeng at bigpond net au , remember to place a dot between the words "bigpond", "net" and "au" leaving no spaces.

 

[multiproducts]

Sorry, I am using the (measured value) X (P/Pi) and then the ACOS of that value. I am using our optical comparator to measure across the teeth by the method you explained. We must have some poorly cut gears here because I am getting PA values all over the place. I am getting very consistant repeatability with the comparator measured values.

 

[jmaurel]

hello, gearcutter's answer is perfectly good,I can send you a quick explanation with drawing. If you want it, contact me at:jacquesmaurel at yahoo.fr