UNEF Thread Specification Geometry

[jimbod20]

I'm looking through the UNEF thread specification standard and have a question.

I'll use .625-24 UNEF-3B for this discussion. The standard defines the minor diameter as .5800-.5869. The standard defines the pitch diameter as .6018-.5979. The standard defines the major diameter as .6250 minimum. I do want to make sure I don't end up with a thin wall in my threaded part. What dictates the maximum allowable major diameter?

I have the same basic question on the .625-24 UNEF-3A thread standard. What governs the minimum allowable minor diameter if the maximum allowable minor diameter .5739.

 

[hydtools]

The thread form as located by the pitch diameter.

Ted

 

[jimbod20]

Thanks Ted.

 

[Pud]

The maximum diameter is limited by the thread angle from the max pitch diameter. That's why it's not toleranced in standards. Pitch diameter is the important bit.

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[jimbod20]

Thanks Pud. I understand now.
I found some online calculators that are most helpful.