Gear / Spline Gaging - Both Internal and External Splines

[True Position]

Recently I've been tasked with gaging a large number of both internal and external splines. The company I work for will not be manufacturing these multiple splines, so fixed gaging is basically out.

The charactaristics it seems the customer is most interested in are Major Diameter, Minor Diameter, Pitch Diameter, and Tooth Thickness.

For OD splines, I've used hand micrometers (and gage pins) for the Major/Minor/Pitch in the past at previous employers, but I'm unsure if the accuracy is going to be high enough, and then there's the issue of the ID splines and Tooth Thickness. My knowledge of gaging tooth thickness is somewhat limited, reading my textbooks doesn't include much, and the machinery handbook includes a moderately convoluted formula that works off the pitch diameter.

My basic question is, what do the rest of you use in the situation? Am I looking at something like a Universal Supermicrometer/Bench Gage?

[Claes Gefvenberg]

In Reply to Parent Post by Hawat

My basic question is, what do the rest of you use in the situation?

Questions first:

Why is fixed gaging out? Any mistakes will cost you, and a large number could make it worthwhile. How large a number?

Your avatar leads me to assume that you have a CMM at your disposal? So did I once, and for the most commonly used dimensions, I used to get probes (balls) in the same diameter as the gage pins (a bit expensive, yes), and use them to measure cross sections along the splines (one needs to be careful, though. Anywhere near tol limits, and you need to check it with a better method. After all, the requirement is for the entire spline).

/Claes

[True Position]

Fixed gaging is out because we are only going to be checking on average 8 of each spline per month and there are several of them. The costs of fixed limit gages for a number of splines(each spline in a transmission) gets quite expensive for marginal results.

As to the CMM, I've tried in the past to use it for major(external), but your typical rolled spline isn't very flat near the top and I was having pretty wildly fluxuating results, I couldn't imagine what my GRR would look like. For minor(external) you'd need some very fine probes to get close. As to pitch, I never did consider getting custom CMM stylii. Your procedure was then, to probe each of the gaps, determine the diameter, subtract the probe diameter, and use that as your measure over pins? Ingenious.

I contacted Zeiss about their GearPro Involute software and Rotary Table, sadly the line of machines that I was purchased cannot use this software.

When you said you used a more accurate method, what are you talking about? M&M Profile checker?

[Claes Gefvenberg]

In Reply to Parent Post by Hawat

Your procedure was then, to probe each of the gaps, determine the diameter, subtract the probe diameter, and use that as your measure over pins?

Exactly

In Reply to Parent Post by Hawat

When you said you used a more accurate method, what are you talking about? M&M Profile checker?

That, I'm afraid, was when I went back to my trusty pins + gage blocks (internal) and pins + micrometer (external)... I just used the CMM to weed out the parts I needed to have a closer look at.

/Claes