can we use total runout with projected tolerance zone?

[Gopinath K]

HI
can we apply total runout with projected tolerance zone instead of position tolerance.
while both ends of Outer diameters are A and B.
how to measure projected tolerance with pos and runout
plaese suggest

 

[greenimi]

If you understand the definition of the projected toleranced zone and also understand the definition of the runout (as defined based on the standard you are working on) then you will have your answer.
My answer is NO, but you might come up with different answer based on your own evaluation of such said definitions.
You can replace position with runout, but then you have to remove Ø and circled P)

 

[axym]

Gopinath K,

To measure Position with a projected tolerance zone, the axis of the hole also needs to be projected. This can be done physically by inserting a snug-fitting gage pin and measuring the axis of the pin over the projected segment. Or it can done mathematically by measuring the axis within the hole and then extrapolating it to the projected segment.

Total runout is usually inspected using a dial indicator directly on the surface of the hole, as the part is rotated about the datum axis.

I'm wondering what the reason is that you want to apply total runout with a projected tolerance zone - is there a specific requirement that you're trying to capture I agree with greenimi that total runout cannot be applied this way. I suppose that it's possible to project the total runout tolerance zone, but projecting the surface of the hole isn't really possible.

Evan Janeshewski

Axymetrix Quality Engineering Inc.

http://www.axymetrix.ca

 

[Gopinath K]

Thanks for your thoughts
I knew that Run out is surface control and Position tol is axis axis control in this case,
my SQA team is asking to change to runout instead of pos tol for projected tolerance since they will insert a pin and check with dial on pin surface they are asking this change.

we use ASME standards for GD&T, is any standard shows way of measuring methods for projected tolerance ?

 

[3DDave]

Runout is for controlling relative deviations of the surface. If they are not measuring the surface they aren't measuring runout.

Frankly, let them. They don't know enough to realize it is a nonsense substitution. It is allowable to do whatever they want; no one is going to take their toys away if they create a special procedure. Just realize that there will be trouble if anyone who does know how to read a standard doesn't want to go along.

Measure projected tolerance the same way any pressed in pin would be inspected for position tolerance RFS, based on finding the axis.

 

[axym]

Gopinath K,

Interesting.

Dialing (checking the Full Indicator Movement) of the inserted pin would be measuring something that is not defined in Y14.5. As Dave mentioned, this is not the same as total runout.

I haven't fully thought it through, but I believe that the total runout value of the projected pin surface would be equal to the position value of the projected axis (assuming that the pin is perfectly cylindrical and the actual tilt angle of the pin is small). Perhaps one of the other forum members can check my logic on this.

My recommendation would be to leave the specification as position with projected tolerance zone, and allow them to inspect it by dialing the pin.

Evan Janeshewski

Axymetrix Quality Engineering Inc.

http://www.axymetrix.ca