Does anyone know where I can get specs on a 3/4-16 UNJF-3A Threads.
I know the mil-spec is mil-s-8879 or as-8879, Thanks for any help.

http://mrainey.freeservers.com/Miscellaneous/unjf.jpg

why that's might nice looking software. What the name of it?

Since you asked, it's call ME Threads. Covers 1100+ different threads, makes a nice printout, costs fifteen bucks.

Read more at http://mrainey.freeservers.com

At fifteen bucks, even a cheap cranberry stained Swamp Yankee. like myself would buy it. Last week I broke three taps and it was more fifteen bucks. Do you take paypal?

Sure. There's a Buy Now button here.

http://mrainey.freeservers.com/PurchaseInfo.html

Thanks so much. I searched the internet for at least 2 hrs without any success. I knew the only difference between the UNF and the UNJF is the tighter root diameter and I needed to know the radius tolerance on the root.

Very cool software. Thanks for the link.

I needed to know the radius tolerance on the root.

Look at that screenshot in post #2 from that nice gentleman it say root radius 2nd row from top right

I know you're doing an external thread this time, but just in case you ever do a J-series internal thread, notice that the minor diameter is larger than the one on the UNF.

Thank Lakeside,

I saw it.
I meant that I posted the question becuase I was only missing that spec.

:cheers: Z zero I have to tell you the truth I been using Mike software for sometime now I have ME Pro and it great to have in the shop. I kindda puy Mike R on the spot today Sorry Mike it will not happen again untill next:cheers:

Thanks mrainey
I guess it would have to be opposite for the internal. Hopefully I will not have to make any internal threads.

Hi Mrainey,
Do you have data for premium connection (casing and tubing) such as NVAM, Hydril, EUE8RD, etc? Thanks. Asuratman.

Do you have data for premium connection (casing and tubing) such as NVAM, Hydril, EUE8RD, etc?

Sorry, no.

The UNJ style threads are used in high stress applications.

Although you could probably cut them (the root radius might be hard to maintain as it is not "sharp"), the most common method for forming them on bolts was via rolling, usually after heat treating.

The J form offers superior fatigue resistance of a conventional thread due BOTH the size/shape of the root but also due to the rolled after heat treat forming process.

Essentially, it is my understanding that this thread was concieved by SPS for aircraft use to be a "cold forged" rolled thread, by which the process work hardens the material thus locally increasing the thread's tensile strength and toughness where it is more highly stressed.

Yes it was designed for aircraft work and rolling would be the best method although the material I am using is 50-55 rockwell. We bought a expensive roller and it would not even come close to doing the job. Thanks for the info.

Ken

The typical bolt/stud materials I'm familiar with that meet that UNJ thread spec are NEVER run at that high a hardness level.

For example: 8740 is a material that is commonly used for rolled after heat treat, cold headed fasteners. Typical pre-rolled hardness is in the HRC 29-32 range - a good compromise for harness and toughness. Most of the alloy steels become quite notch sensitive as you get into the HRC 50-55 range.

Thus, cutting threads could leave some serious stress concentrations that could become problematic. If it is an OD thread, you might want to consider grinding the threads. This could be less stessful if done properly than die or tool cutting the materials.

You might also want to to a stress relieve (250~350F for an hour or so) after thread cutting or grinding (check with a metallurgist for the proper time/temp for the material you're working with).

Some materials get very, very notch sensitive when you cut threads and then do NOT stress relieve them properly afterwards. This is also the case with some materials when you grind them -

Technically, you are frying the material when you grind. Why else would there be sparks coming from the material when it is cut by grinding???

Whatever you do, it won't hurt to be real carefull.

i want to know what is profile detail of thread.

MIL specs...

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

Type just the numeric part of the spec (8879) in the "Document Number" text box and hit "submit"... it'll give you everything in the spec.

Anybody here know where to find data for premium connection on casing and tubing such as hydril, VAM, etc. Thanks. Asuratman.