Thread Issue 1

[bryjarmoc]

We have the following issue:
We have a shaft Outside threads. The Go Gage will not "GO". However, the parts fit to the mating part AND the mating part checks "good" using Thread Plug Gage.

How can this happen?

 

[MintJulep]

Your GO gage is bad?

 

[bryjarmoc]

Go Gage is good, and we used 2 other go gages with the same result.

 

[CoryPad]

Use functional gages and compare to thread specification limits for both internal and external threads. Sometimes simple gages cannot identify fit problems.

 

[TVP]

The Johnson Gage Company has a great deal of experience with this issue. Take a look at these links for some insight:

http://www.johnsonthread-view.com/pdf/Thread_View_Importance.pdf

http://www.johnsongage.com/news.aspx

 

[dgallup]

Just because 1 mating part fits does not mean that ALL mating parts will fit. You GO gage will guarantee that all mating parts will fit.

 

[KENAT]

As dgallup says, a go gage is checking one of the limits of permissable tolerance. It is toleranced to be up at that limit.

Real mating parts on the other hand are quite likely somewhere in the middle of their permissable tolerance range so are more forgiving of other parts being outside of their permitted tolerance range.

Posting guidelines faq731-376

http://eng-tips.com/market.cfm?

(probably not aimed specifically at you)
What is Engineering anyway: faq1088-1484​

 

[bryjarmoc]

What is the difference between 1.00-32 UN-2B thread and a 1.00-32 NS-2B Thread?

 

[mrainey]

"What is the difference between 1.00-32 UN-2B thread and a 1.00-32 NS-2B Thread?"


Look here:

http://www.eng-tips.com/viewthread.cfm?qid=92960&page=5

Software For Metalworking

http://closetolerancesoftware.com