[Healeys] nut type for Smiths heater assembly for BN2

[Curt/Nancy Arndt]

Tadek,

As a rule of thumb, a BN1/2 will have three different and distinct thread
forms present;

*Whitworth*, mostly BSF and one or two BSW applications, found in the
engine, transmission and suspension with changeover to UNF in some of the
suspension parts in later cars (BN2s.)  Also some BSP (British Standard Pipe
- Parallel) applications in the engine.

*Unified Threads* and once again mostly UNF and I can't think of any UNC,
mostly in the body and chassis and all miscellaneous applications.  UNF is
essentially the same as SAE Fine Threads and interchangeable.  UNF/UNC
fasteners are marked to distinguish them from Whitworth Fasteners,  and
finally...

*BA (British Association)* found primarily in the Smith's gauges, fuel
pumps/sending units, and wiper motors. Be careful however as No. 2BA is very
close to a standard UNF/SAE Fine 10/32 thread and a 10/32 nut will thread
onto 2BA stud or screw and vice versa.  However a 10/32 screw will not
thread into a deep 2BA tapped hole.

And NO British Association is NOT a Whitworth Thread!!!

Cheers,

Curt

On Sat, Aug 7, 2010 at 12:03 PM, Tadeusz Malkiewicz <
tadeusz.malkiewicz at plusnet.pl> wrote:

> Hello,
>
> Anyone knows what is the thread type on the heater motor studs? It's
> definitely not UNF/UNC..
>
> I lost 2 nuts :-(
>
> Best, Tadek