gear measurment over wires

[itsmeclay]

I would like to know how to find the high and low measurment over pins limits for a given involute pline gear

please direct me to info to do this

 

[israelkk]

This is too complicated for this forum. You need to know the mathematical basics of involute gears/splines. The problem is to understand how the manufacturing tolerances given by the gear/spline spec affects the chordal tooth width. Without knowing how to calculate it you can not calculate the dimension over pins.

All the calculators (and you can find few free on the net) assumes that you know the tooth width on the theoretical pitch diameter. However, this is the catch, how to calculate the tooth thickness knowing the tooth tolerances, such as: tooth thinning, tooth width tolerance, total composite tolerance, etc., only then you can use the formulations to calculate the dimensions over pins.

Dimension over pins is quite expensive and time consuming process because to correctly measure the gear/spline you need to perform this on all pairs or teeth. Assuming 60 teeth gear/spline you will need 30 measurements for each spline. A much more accurate and cheap method is using rolling test against a master gear (at least for involute gears it is a common practice).

If you have the time and will you will need to invest some time to master the issue. I recommend that you get a good book such as dudley's GEAR HANDBOOK and other books such as AGMA manuals. The subject is not covered in one place you will have to gather bits of information here and there to completely learn the issue.