thread class - 3A screw in 2B hole?

[bdown]

hello,

i'm wondering if anybody can share some thoughts on mixing thread classes. specifically, what would be the potential problems versus a 'proper' class 2 or class 3 thread. thanks!

 

[KENAT]

Class 3 in class 3 allows a line fit at max tolerance as I recall.

Class 2 in class 2 always has a certain amount of clearance.

A class 3 screw in a class 2 hole will have a fit somewhere between these 2. So, simplistically, it will be 'tighter' than a 2 in a 2 but looser than a 3 in a 3.

It will be more tolerant of 'contamination' in between threads than a 3-3, but not as tolerant as a 2-2.

Take a look at ASME B1.1 to better understand unified thread tolerances.

What is your application?

KENAT, probably the least qualified checker you'll ever meet...

 

[MotorVib]

I have mix the thread class in the passed and have nor problems. Take a look at the ASME.

Chris

"In this house, we obey the laws of thermodynamics." Homer Simpson