What's slightly bigger than an 8-32 thread?

I would definitely try an M4 and an 8-36. Have you mic'ed the stuff to get a good major diameter and/or measured the thread pitch?

Sent from my Pixel XL using Tapatalk
 
extropic said:
Slightly is not a well defined unit of measure.
Click to expand...
Beat me to it.

The idea that the ends may be peened seems pretty likely. As recommended, measure the OD and thread away from that area to see what it really is. Hard to believe that a US mfg (even in the 1950s) would use a non-standard thread for that application.
 
Superburban said:
The diameter difference between the 8-32, and the 10-32 screws are only 0.03"
Click to expand...

In context, that is a significant difference in size. A 10-32 nut will just about slide on to an 8-32 stud with no thread engagement.
Note that the OP stated the nut he had was a good fit on the store's thread checker. This also pretty much rules out M4 and 8-36, neither of which will thread on to an 8-32 stud without force and thread damage.
 
Use a thread gauge to confirm that it is a 32 t.p.i. thread. Then run a 8-32 die on the posts that are too big. Your new nuts should work now.
 
RobertB said:
RJ that die is actually 9/32 - 32, not #9-32
Click to expand...
Thanks Robert My mistake! I need new glasses or more coffee.
MSC does sell a #9-36 tap though. However, I could find no reference to a #9-32 thread. It is possible it could have been a proprietary thread by the manufacturer.
 
Superburban said:
The diameter difference between the 8-32, and the 10-32 screws are only 0.03"
Click to expand...

Thanks for everyone's comments. The quick answer is the mystery thread on my vintage device is 10-32.

Looking back at it now, I wouldn't call a 10-32 nut on an 8-32 stud a "good" fit. When I tried this again, the nut I tested does thread rather than slide, but it's pretty wobbly. By comparison, when I put the mystery nut on a 10-32 stud it's a very solid fit. And vice-versa for a 10-32 nut on the mystery stud.

In any case I appreciate the posts, and picked up a few ideas. BTW I do have several mikes and a thread pitch gauge, but what came in the handiest was when I was digging around in drawers I found a pair of inch and metric sets of "Thread Detective" testers. This allowed me to verify 10-32 and rule out at least the other common nearby sizes.
 
Frank O said:
Thanks for everyone's comments. The quick answer is the mystery thread on my vintage device is 10-32.

Looking back at it now, I wouldn't call a 10-32 nut on an 8-32 stud a "good" fit. When I tried this again, the nut I tested does thread rather than slide, but it's pretty wobbly. By comparison, when I put the mystery nut on a 10-32 stud it's a very solid fit. And vice-versa for a 10-32 nut on the mystery stud.

In any case I appreciate the posts, and picked up a few ideas. BTW I do have several mikes and a thread pitch gauge, but what came in the handiest was when I was digging around in drawers I found a pair of inch and metric sets of "Thread Detective" testers. This allowed me to verify 10-32 and rule out at least the other common nearby sizes.
Click to expand...

Isn't the internet wonderful! We have access to all sorts of fresh and interesting challenges. :grin:
 
Frank O said:
what came in the handiest was when I was digging around in drawers I found a pair of inch and metric sets of "Thread Detective" testers.
Click to expand...

Hey, what a coincidence, I just got delivery of some more of those today!

I initially picked-up the "Standard Combination in/mm" kit from KBCTools: https://www.kbctools.ca/itemdetail/1-842-405

I found that quite innovative and handy, so started looking for the other kits.
Their website is here: http://threaddetective.com/
(look under Products - Thread Identifiers)
They only want to sell in quatities directly, however they have two US suppliers.

I just got the mini and the jumbo combination in/mm sets delivered today from
https://www.pegasusautoracing.com/group.asp?GroupID=DETECTIVE

No connection to them except a happy customer!

-brino
 
You must log in or register to reply here.
Back
Top