I have this type of pressure switch fitted:


Fitted to this type of t piece:



The switch has failed so I bought a new one as above (listed as for a mini) but the thread is too large.

I've taken some measurements of the old switch and the thread is a taper thread, max diameter is just under 3/8" and the pitch is approximately Metric 1.0 (only have a metric thread gauge) Anyone know what this corresponds to?

The new switch is approx 1mm larger diameter and a similar thread pitch..

The 2 threads used are 3/8"x24TPI UNF and M10x1 metric.
The tapers complicate things a little but the metric thread is about 0.5mm larger in diameter. A classic Mini is likely to need the UNF thread.

Mal

Looks to be the 3/8 UNF one then as 24 tpi is just under 1.0 thread pitch from what I can tell from google. (25.4 tpi would be 1.0)

I'll have a look about and see if I can get one from the local motor factors.

Thanks!