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Who woulda thunk...there's Metric on my car!

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emmett1010 said:
Moss part #361-020, Knurled nut, brass, for 5mm studs.
Emmett
Click to expand...

I'm wondering if Moss is using that "5mm" size to differentiate between a common 10-32 and what it actually is...which I believe is a 2BA thread. They list that as also fitting the early MG TC&TD gauges, and I bet that they weren't metric. Nominally, 5mm (.196"), 10-32 (.190") and 2BA (.185") are very close in diameter. I may be wrong, but I don't think that Moss part is a 5mm metric.
 
Sorry to dredge up this old thread, but I thought it better to use it than start a new one. On my post-60000 TR3 I have one knurled nut that fits perfectly, but the other side was missing. I read the Moss catalog and saw the 5mm size designation for the stud, and mine measure right at 5mm od. So today I bought some M5-.80 wing nuts but they won't screw on. I really don't want to pay Moss $8.99 each for the knurled nuts. Has anyone ever found a much cheaper alternative? Thanks!
Regards,
Bob
 
From my hardware store(circa '70s) I have some M5 hex nuts from an assortment from Hillman Fastners.
They fit the studs however they are not winged or knurled.
 
Thanks Phil! Can you tell me the metric "pitch" of those nuts? The .80 pitch I bought don't fit the threads on the tach studs. Thanks!
Regards, Bob
 
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TuffTR250 said:
Sorry to dredge up this old thread, but I thought it better to use it than start a new one. On my post-60000 TR3 I have one knurled nut that fits perfectly, but the other side was missing. I read the Moss catalog and saw the 5mm size designation for the stud, and mine measure right at 5mm od. So today I bought some M5-.80 wing nuts but they won't screw on. I really don't want to pay Moss $8.99 each for the knurled nuts. Has anyone ever found a much cheaper alternative? Thanks!
Regards,
Bob
Click to expand...

I just checked the threads on one of my old speedo units, and they are 2BA (British Association) threads. Moss shows that knurled nut fitting TR2 thru TR4. They are not 5mm nuts, although the major diameter is close (see my above post from 2009). Below is some info from British Fasteners about different British threads, including BA threads. They explain how BA threads are deduced. "47-1/2 degree thread angle. This is a metric thread system devised by the British for small screws used in components like speedos. Not metric like you might expect, but with diameters determined by a factor proportional to a power of the logarithm to the base 10 of the thread pitch in millimeters." They also sell taps and dies etc. If you had a tap, you could always make a nut, but a 2BA tap from British Fasteners is almost the same price as the nut from moss, but then you'd have the tap.

Edit: BTW, there are more BA threads on the TR3. Most threads smaller the 1/4" are BA. I bought a couple of 2BA and 4BA taps and they will fit just about any smaller screw that you find.

https://britishfasteners.com/index.php/threads-ba


 
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