Special Gages for Measuring Pre-Heat Treat Thread Size

[samsga]

We thread holes in shafts and have go/no go thread gages designed to fit finish part. Operations was running to this gage pre-heat treat. We have done this in the past and ran to 1 1/2 to 3 threads on the no/go gage and it worked fine. I'm getting push back now to order "special" gages for the pre heat treated parts. Just wondering how other people handle the shrinking thread size in carbon hardened shafts?

 

[Stijloor]

A Quick Bump!

Can someone help?

Thank you very much!!

 

[iamtroll]

Running a part on the NO-GO gage is only a guesstimate since you are not checking the major or minor diameter but just the pitch diameter. If you can justify the cost and you understand the changes that the heat treating is making on your threads then a set of preheat treat GO, NO-GO gages would be the recommended option.

Hope this helps.

 

[Michael_M]

We use quite a few pre-plate gauges

The gauges are kept in a separate location from the 'normal' gauges to keep them from getting mixed up. I have found this to be very important to keep mistakes from happening.

The gauges are marked with the pitch diameter so we can find the exact one needed. We have some thread sizes that get a plating that is .0002 max thick while other parts (same thread) have a plating that is .0002-.0005 thick. We have different gauges for each.