using UNF-2A with UNF-3B ?

[edleit]

I am designing a threaded connection that uses a tie rod of known length which, when tightened, will enable me to determine the compressive load on the parts being squeezed by measuring the rod and calculating based on the resulting stretch. The tie rod is of Titanium construction with 1/4-28UNF-2A threads. I have been asked to consider using silver plated lock nuts to reduce friction and potential for galling. The nuts are available as a common item for aerospace applications in Class 3B.

The Ti tie rods will be raw (no plating/coating).

I know that there is a difference in tolerance for Class 2 vs Class 3, with 3 having the tighter dimensions.

The assembly will be operated in a static condition (no moving mechanical parts), mounted to a baseplate, so vibration is not a concern.

Is there a problem mixing thread classes?

Thanks,
Ed

 

[zekeman]

Not for this application.

 

[KENAT]

Class 3 effectively means you can have a line fit as I recall.

So from a simplistic fit point of view male 2 will fit female 3 and vice versa.

Posting guidelines faq731-376

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

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