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Circular or Total Runout Gears and Splines?

optomist1

A Sea of Statistics
Trusted
#1
Hi To All,

I have a question regarding the use of Runout Controls as applied to a Gear/Spline combination. If given a gear/spline (coaxial diameters) combination and I wish to use a Runout tolerance of say 0.1 to control the the pitch diameter of gear teeth relative to spline pitch diameter. Is it preferable to use a Total Runout vs a Circular Runout? Or am I missing something? Doing so seems to be a better indicator or measure of the relationship of spline teeth to gear teeth. The inspection set up would see to be the same.

Thank you for your assistance...

Marty
 
T

True Position

#2
Re: Circular or Total Runout Gears and Splines??

What method were you considering using where runout and total runout are similar to check?
 

Stijloor

Staff member
Super Moderator
#3
Re: Circular or Total Runout Gears and Splines??

Hi To All,

I have a question regarding the use of Runout Controls as applied to a Gear/Spline combination. If given a gear/spline (coaxial diameters) combination and I wish to use a Runout tolerance of say 0.1 to control the the pitch diameter of gear teeth relative to spline pitch diameter. Is it preferable to use a Total Runout vs a Circular Runout? Or am I missing something? Doing so seems to be a better indicator or measure of the relationship of spline teeth to gear teeth. The inspection set up would see to be the same.

Thank you for your assistance...

Marty
Total Runout would be a more logical choice because it verifies the entire length of the controlled feature. The tolerance zone is the radial distance between two coaxial cylinders.

Please note that Y14.5-1994 in clause 2.10 (page 29) requires that the specific feature of gears and splines must be specified. For example Major Dia, Pitch Dia, or Minor Dia. There are companies that make specific gages to verify particular characteristics.

Here is an example of such a company.

Stijloor.
 

optomist1

A Sea of Statistics
Trusted
#4
Re: Circular or Total Runout Gears and Splines??

Good Morning True Position,

My choice is Total Runout as it controls the entire part length, as opposed to discrete circular elements....

Thank you for the response..

Regards,
Marty
 
T

True Position

#5
Re: Circular or Total Runout Gears and Splines??

Good Morning True Position,

My choice is Total Runout as it controls the entire part length, as opposed to discrete circular elements....

Thank you for the response..

Regards,
Marty
I understand the difference between the tolerances, but they are very different to manufacture and measure. Total runout (in my experience) is more costly and grows significantly in difficulty with the length of surface it is applied to.

If your processes are so good that it is completely cost cost neutral to you, then obviously yes, use total runout. I just find it surprising that they would be cost neutral.
 

optomist1

A Sea of Statistics
Trusted
#6
Re: Circular or Total Runout Gears and Splines??

This question came up as part of my preparation for the ASME Technologist exam, somewhat hypothetical....thank you for your help...

Marty
 

optomist1

A Sea of Statistics
Trusted
#7
Re: Circular or Total Runout Gears and Splines??

Good Day Stijloor,

Thank you for your response; I agree with you, in this case the feature for the spline and gear are both shown as Pitch Diameter.

From a GD&T green horn, it appears use of a circular over total runout would be appropriate when the functional area of concern is dimensionally very narrow, instead of the full part length.

Thanks for the site link....

Regards,
Marty
 
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