TR4/4A Starter Terminal

[TBU_Triumph]

Hello to all,

I just finished disassembly, cleaning and reassembly of the started for a 1966 TR4A. Overall things were in very good condition. I did have to solder a new terminal to the field coils. The threads were stripped on the old one.

I only have one brass nut which I used to reinstall the terminal into the end housing. I was thinking I could use a 1/4-28 regular hex nut for the second one.

However, even though the threads measure at 28 per inch the nut will not install by hand. It starts ok but by the time the nut is fully engaged it will no longer turn by hand. I do not want to force things and mess up the new terminal.

Is there something special about the threads on that terminal? My guess is that this question has been asked and answered many times. However I was not able to find it through the search engine for the forum.

Thanks for the help,

Rusty

 

[TR3driver]

Yeah, they're British threads. 0BA if I remember right, which is actually 25.4 tpi (but impossible to tell from 28 without a strong magnifying glass).
A M6x1 nut will probably work (but the thread angle isn't quite right); or a quick Google turned up this place in Australia that says they have 0BA brass nuts and will ship internationally (tho shipping might be expensive)
[url]https://www.classicfasteners.com.au/std-hex-nut-brass-0ba/

Don't forget the nut has to be insulated form the end plate.
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[TBU_Triumph]

Hi Randall,

Thanks for the confirmation that they are unique threads. I might try a metric 6 x 1 nut.

And thanks for the reminder on the end plate insulation. I have the plastic sleeve and fiber washer in place. I also have a sleeve over the terminal post where is goes past the brushes as well as the paper insulator around the end 0f the coils at the brush end.

Electrically everything works great and the starter drive jumps into place especially after I cleaned it and reassembled it no grease or oil.

Rusty