There are a few oddball fasteners used in E-types.Today, I lost one of the nuts that holds my dash top in place and discovered that 10-32 hardware was very tight. I “cleaned up” the threads by running a hardened nut down the stud, and then it was fine. But I’m thinking these were actually tapped for 2BA, and it was just lucky that what I did worked. You live, you learn.
after many years I just learned that there is a thread called 2BA myself.
I think I “cleaned up” more than a few to 10-32 as well. oh well
Boy am I glad to learn this!
Back in November I launched a lengthy thread (no pun intended) titled - “A very unusual thread - resolved” - trying to find out why my dash fasteners were not working with 10-24 nuts, etc.
When I removed the dash top on my 69 2+2, I was puzzled that there were no nuts on the two center mounting studs. Removing the nuts from the end studs had been a challenge. One was a pressed-on speed nut that had to be broken, and the driver’s side was very hard to remove and appeared to be cross-threaded.
Nothing I had would fit the studs, nor did they match any of my UNC or UNF thread checkers, or even metric!
A check in the parts book showed the nuts to be UFN.119/L, which I learned is 3/16’’ UNF, at 24 tpi. This size is not listed with major fastener suppliers - BoltDepot, Fastenal, McMaster etc. They all go from 10-24, 10-32 to 1/4-20, 1/4-28. There’s nothing between 10-32 and 1/4-20.
Ultimately I concluded that the tolerances in my 10-32 thread checker were at fault. It would NOT thread onto any of the four dash-top studs without binding immediately. However it would readily accept any of the 10-32 screws that I have.
I have yet to re-install the dash, but perhaps that can be accomplished successfully by using the correct nuts!
So if these are truly 2BA threads, I see that we can purchase nuts here:
In the UK at
or domes at
or in the US at
http://britishfasteners.com/index.php/nuts/steel-nuts/steel-ba-nuts.html
I will do so and report back.
Does this mean that replacement dash tops continue to be manufactured with this odd thread?
It’s probably a UNC #12-24. A 1BA is only sort of close to a UNF #12-28.
If you’re looking for stainless #12 fasteners in the US, try albanycountyfasteners.com .
Ron
Tom,
You need to be careful with these small threads as it is easy to mismatch and not be aware.
Re-starting:
If you say the parts book says the Nut is UFN.119/L it is as you say originally a 3/16"UNF, but that size less than 1/4" became obsolete, and by the 1960s the smallest UNF size you could have was 1/4"UNF (and that was 28tpi). I will have to dig out my old British Standards, but 3/16" UNF was never 24tpi so I don’t know where you got that from, that sounds more like the also obsolete 3/16" UNC.
A UNF.119/L in the 1960s was now a No.10-32 so .1900" major diameter and 32 tpi.
The old obsolete 3/16"UNF was 0.1875" major diameter (and I think also 32 tpi), so under normal manufacturing tolerances, easily interchanged without damage.
A 2BA thread however is smaller again at 0.1850" major diameter, and has 31.4 tpi, so doesn’t really fit all that well.
So be careful, although Jaguar were very quick to adopt UNF threads (both 3/16"UNF and No.10-32 are UNF), with small threads (defined as less than 1/4" diameter, there is still quite a lot of BA threaded fasteners used, especially on items bought in from sub-suppliers such as Lucas and Smiths. But as you have - always check the Spare Parts Book first and find out exactly what the thread should be in the first place.
BA nuts, setscrews, taps and dies can all be readily purchased, but usually from specialty fastener outlets, and not main stream suppliers.
Roger
I’m going to stick with 2BA as my best guess, but there were a lot of competing standards at the time which would ‘almost’ interchange: 3/16 BSF, 3/16 BSC, 10-32, 2BA and, just for fun, 5mm x .8. Since my studs are now worked down to 10-32, it would probably help some future restorer if someone could try a 2BA and see if it works.
I have already ordered some. We shall see.
Well, I have just received my 2BA fasteners and am the proud owner of 4 brass nuts, 4 steel nuts, 4 nyloc nuts and 2 cap nuts - all in the unusual thread/size of 2BA. (I had to meet the minimum order amount).
Guess what - they don’t thread on to the 4 studs on the upper dash. They look to be the correct diameter, but there is no match on the threads.
Being an OCD fastener guy, I will add them to my collection. If anyone can use them let me know.
What does fit pretty well are 3/16 - 24 nuts (10-24 does not), and I am wondering if the real thread here is 3/16 inch Whitworth.
I’ll order several and let you know.
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Try 5mm-.8. At least it’s something you can find in the hardware store.
Mike frnak
I recovered an old BA tap and die set from UK on my last visit on the off chance it might be useful. Still wondering if it might be of use!!!
Tom,
I’m confused by this, but I’m easily confused.
Having precise measurements is important to identify fasteners. Test fitting alone is perilous.
If you are absolutely confident that the stud’s major diameter is 0.175 to 0.185" and the pitch is 24tpi, the neanderthal approach would be the simply chase your studs with a UNC #10-24 die, and be done with it.
The purist approach would be to verify the thread profile with a Whitworth thread gauge. If it very closely matches the BSW 3/16 profile, that is likely what you have, and the threads are either damaged, deteriorated, or of lax tolerance. If you go this route and obtain some BSW 3/16 nuts and they don’t immediately fit, try painting the stud with Dykem blue (or a Sharpie) and hand fit it. That will show where the threads are binding. If it’s binding at the stud’s minor diameter, the simple solution is to carefully file the inside of the nut until it fits well. Chasing the stud with a BSW 3/16 die is also an option.
Even if you are extremely careful, things can still go wrong. I have many tales of woe regarding fasteners on British cars and British antiques. Persevere.
Ron