Acme threads

[HRP21]

Hi,

I have 4.125-3 Acme- 2G external threads. The threads are worn out due to its use under high pressure. But I know those are still going to be good for some more wear. Obviously it passes thru Go and No-go gage. What I want is to come up with some no-go gage for these worn out threads. I cannot find 1G dimensions for these threads. I am not even sure if 1G exists. Can somebody help me with this, should I change the PD or major or something else .

Thank you

 

[geoffthehammer]

My reference book - Machinery's Screw Thread Book- lists the classes for American Acme as 2G, £G, 2C, 3C, 4C, 5C and 6C only. Perhaps 1G does not exist but it would seem strange to atsart at 2G. It would seem that you will have to delve into the history of the thread to find an answer.

 

[MintJulep]

I would use your 2G Go gauge and measure the axial free play with the gauge fully threaded on.

Don't know what the limit would be, but it would be a fairly straightforward calculation to determine the available load capacity once the thickness of the remaining thread is known.