Checking Concentricity and TIR 1

[Porknar]

A little help here. We have an old print for a shaft that reads "Diameters to be concentric within .001 TIR" Now these diameters are differnet sizes ranging from 11" to 19.5" over a shaft that is 66.5" long. Can anyone offer a defintion and an inspection method. We are having a dispute on how to go about this. Any help is greatly appreciated.

 

[Michael854]

Jim,

I know a fortune 100 company that starts with a C that has hundreds of drawings that contain the TIR note.

They follow their own standard which is an interpretation of the ASME '94 standard...er...make that try to follow it.

I saw a 3 yr old drawing that had a size tolerance on a shaft, a TIR to the other end of the shaft, a geometric position callout to the other end of the shaft, AND +/- coordinate dimensions relating features to the centers of both ends of the shaft.

)

(insert circus music)

Michael
GDTP-S0470

 

[DesignBiz]

In my opinion Ringster's "go back in time" to try to understand what the callout meant can be helpful. However, at this point to weigh-in with the part functionality would be very important as to understand how to measure the part relative to function.

I am not so sure to measure concentricity per the 1994 standard would be the way to go, if in fact part function allows for inspection by runout. In fact with the absence of a noted standard, determining the definition of concentricty might be a struggle.

Measure in a way which makes sense relative to part function.


DesignBiz

 

[MechNorth]

Michael, unfortunately to some, the world IS still flat.

Jim Sykes, P.Eng, GDTP-S
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