How to duplicate thread tables in Machinery's Handbook 1

[someonesdad]

I am writing a program that I would like to have duplicate the basic toleranced thread dimensions in Machinery's Handbook (pg. 1276, 19th ed. or pg. 1736, 27th ed.). The book states "... are derived from certain Unified formulas (not shown here) in which the pitch diameter tolerances are based on increments of the basic major (nominal) diameter, the pitch, and the length of engagement." They state they use 1.5*Diam for the length of engagement.

My question is whether anyone can provide these equations. Or, if it's recommended that I purchase an ANSI or ASME standard, that's OK too -- I'd appreciate a reference to the appropriate standard.

Thanks in advance for any help!

 

[monkeydog]

You might try MIL-S-8879. I don't have a copy in front of me, but I think I remember seeing equations for theads in that spec.

 

[Screwman]

For inch fasteners the formulas for design and tolerance are in ASME B1.1, and for metric designs they are in ASME B1.13M. Those are the source documents for the thread standards, so I would recomend using them.

 

[FredGarvin]

You're better off getting the ASME spec like Screwman pointed out. The MIL spec is for UNJ series. It does contain equations for threads but there are some that are referenced to ASME B1.1

 

[israelkk]

FED-STD-H28 SCREW-THREAD STANDARDS FOR FEDERAL SERVICES has 23 parts dealing with all types of threads it can be downloaded from

http://assist.daps.dla.mil/quicksearch/

 

[someonesdad]

Excellent! israelkk, thanks for the URL -- it looks like a great place to search for federally-related specs in the future. The federal ones on threads I downloaded and looked at seemed mostly to reference the source ASME documents. Thus, I think I'll take Screwman's and FredGarvin's advice and try to get my hands on the ASME standards.

Thanks!