Thread size? Mopar Ball Joint

[Bruce Dorsi]

Can anyone tell me the size and pitch of the body threads of a Mopar ball joint?

It is the upper screw-in ball joint, (Moog # K772) and has a 1-15/16" hex.  ....I was told this is the smaller of two sizes of screw-in ball joints which Chrysler used.

I have been able to find the specs of the tapered stud, but I need the size of the body threads.

Thanks for any help.

[kb426]

I found threaded tubes to weld to something but no thread data. I found that to be unusual. Sorry I'm no help.

[enjenjo]

I can't find any specs on the threads, but this company  https://www.lefthanderchassis.com/v2a/16_products.asp?idcategory=1757  offers taps in both sizes, and you might get the specs by contacting them. If you do, post it here.

[Bruce Dorsi]

Thanks, Frank.  

I'll see what I can find out.

[Bruce Dorsi]

I made a call to Moog and this is what I was told:  Moog K772 Ball Joint  -  Body threads 1.841" x 12 t.p.i.

Another source specified the major thread diameter as 1.837".

The socket threads of a friend's tubular s/s A-arm do not have sharp crests.  

From another source:  "The threads around a ball joint are not normal screw type threads, they are very shallow.  ...Because there is not a standard for the 'thread' that was used, there are often dimensional differences between how various ball joint manufacturers turn the threads."

The appropriate tap from enjenjo's link costs $87.50 + shipping for what will be a one-time use. It is described as being used to "repair damaged threads," which to me, sounds more like a chaser than a tap.

Since the sleeve is already threaded, I believe a thread 'chaser' can be made by cutting grooves in the threads of a new ball joint ($15).

A new un-modified ball joint will then be installed.

[UGLY OLDS]

                       

Bob...

[enjenjo]

The major thread diameter is 1.837, and the minor diameter is 1.810 so they are not very deep. In the original application, they are installed under pressure into a un-threaded sleeve, deforming the sleeve ID into threads. More or less self tapping.