Does anyone know what type of screw is this?



Need a couple for some spare speedos I have..

Cheers,

Kostas

email (option): ferrarakias@hotmail.com

Hi
it is for the Cable speedometer Norton 16h
i have one NOS
cheers- Hussein

email (option): sl_hussein@yahoo.com

The thread will be a B.A thread...You should be able to work out which one from the o.d. measurement...Ian

email (option): ian@wright52.plus.com

I make it 6BA Kostas. A short screw that doesn't go right through.
I've used this firm and found them to be very good. http://www.ba-bolts.co.uk/

Ron

email (option): ronpier@talk21.com

Ian and Ron,

Thank you very much!



Hussein,

Don't need a speedo cable, have a couple of the thick ones already in stock but thanks anyway.

Cheers,

Kostas

email (option): ferrarakias@hotmail.com

Pretty sure it's M2,5, like all threads on the speedo's, all metric! Very logical when you think of it, Jaeger was French..... Had a couple made last year, the little screws that is, but just enough.

Cheers, Lex

Well it seems even the experts can't agree on thread sizes

http://www.voc.uk.com/net/docs/10.1/10.1-520-8.pdf

Ron

email (option): ronpier@talk21.com

I still say they are BA...and don't forget the BA thread system IS based on a metric system and uses metric dimensions..

However, it is not a metric thread..Sizes are 'rounded up' to the nearest thousandth of an inch using Imperial measurements and the thread angle is 47.5 degrees not 60 degrees as in metric threads....

The basic thread size in the series is 6mm x 1mm pitch (0BA), other sizes are calculated by applying a formula to these figures...Some charts express the O.D in metric and imperial sizes..

Used by the British when manufacturing components classed as 'instruments', in fact it was frequently referred to as 'instrument thread'...

For motorcycle applications I think carbs, levers, speedos and some electrical equipment all fell into this category...Ian

email (option): ian@wright52.plus.com

Haha Ron, Ian, yes, that is I believe an American article! but then the 2 screws that hold the instrument in the casing, are pure M5, the studs on the case are M6 thread, with a funny size hex, must admit that, had loads of those made too, from originals. (everybody buggers this up with 7/16" BSC/BSF)

But to get back to the little one, I tried same, with a BA tap, and could not get it through all the way, unless I removed quite some material, now with the M2,5 tap, it went in without removing any material, works for me! and this little screw has a taper at the back of the head, don't forget that!

Hope this helps!







Cheers,

Lex

email (option): welbike@ welbXXX.net

I'm with Lex on this one. There is certainly evidence that when Smiths took over production of the Jaeger instruments under licence and as UK agents for Jaeger, they were required to retain full parts interchangeability with the Continental-made clocks.

It does seem that at some later point they altered the hexagon size of the retaining nuts but not the threads.

That must be why my 6BA tap didn't want to go right through the spindle. I didn't want to force it as I thought the thread stopped short. Ron

email (option): ronpier@talk21.com

Great! Thank you all for your help!

email (option): ferrarakias@hotmail.com