TR2/3/3A Gauges held in by "knurled Knobs"?...always losing them.

[karls59tr]

Who sells those round knurled knobs for the back of some of the gauges on the 3?...... or anyone know the thread size so i could put a nut on?:dispirited:

 

[mikephillips]

I expect like my Sunbeam, MG and Jaguar gauges there are two common sizes, a larger one for the big gauges and smaller for small gauges. Moss I believe has both sizes available.

 

[ed_h]

Don't know if this translates to the 3, but on a TR6, the knurled nuts for the tach/speedo and the oil gauge look identical, but aren't. Oil gauge nuts are 8-32, while those on the tach/speedo are 3BA.

Ed

 

[2liter4cyl]

I have one large gage that takes 10-32 nuts, and the other is 5x.75 mm. The small gages are 4x.75mm may be an 8-32 also, but I haven't seen one. Le

 

[karls59tr]

Don't know if this translates to the 3, but on a TR6, the knurled nuts for the tach/speedo and the oil gauge look identical, but aren't. Oil gauge nuts are 8-32, while those on the tach/speedo are 3B.

Thanks for the info.Any idea what size the small screw is on the back of the panel switch rheostat? I missing one screw that would attach a wire.

 

[karls59tr]

I have one large gage that takes 10-32 nuts, and the other is 5x.75 mm. The small gages are 4x.75mm may be an 8-32 also, but I haven't seen one. Le

So metric size screws would work in place of the originals?

 

[dklawson]

Most of the Smiths gauges I have worked with had the BA threads. I bought some taps from British Fasteners online and make my own gauge nuts by re-tapping brass 6-32 thumb nuts from the hardware store.

 

[TR3driver]

Definitely not all the same. On my TR3, original large gauges are M5x.75 (which is a very uncommon metric thread, not found in any set); small gauges are 3 BA. But IIRC it changed before the end of the 3A run.

You really need to identify what you've got first, then look for nuts to fit. HF has cheap jewelers loupes and cheap dial calipers; after that you just need a good thread gauge and a chart like
https://mdmetric.com/tech/tict.htm

 

[pdplot]

Nisonger Corporation?

 

[TRMark]

Once you determine what you need, you might want to check with McMasters-Carr https://www.mcmaster.com/#thumb-screw-nuts/=11cprf4

 

[karls59tr]

Thanks to everyone for the input.:eagerness: