Shaft and nut size

[Joust]

I've got cheap a secondhand pub lager tap that I'm using as a 2nd tap with my home bar. But it's missing it's nut that goes on the shank which secures to the wall or whatever your using.

Anyone got any tips on measuring it to work out which nut to buy?

I've drilled a 20mm hole in the wood part of my bar, and the thread from the shank screws in to the 20mm hole pretty nicely. To the point I probably don't even a nut.

But I probably want to do it properly before the hole gets worn out.

How do you measure a thread? Peak to peak or trough trough? And then count the threads?
How do I know if it's proper measurements or old school inches and fractions?

Is there some sort of standard?

 

[Drunkula]

All signs point to 7/8" x 14. Can ya dig it?

 

[Joust]

All signs point to 7/8" x 14. Can ya dig it?

It looks like a maths equation. Do I do the division or multiplication first...

Or perhaps old money? Like 7 bob 8 shillings and 14 pence.

But thank you. That's something I can work with. Very helpful.

 

[cushyno]

Measure OD (outer diameter) and number of threads, either threads per inch or thread pitch in mm. That should give you a good start. If it's an imperial thread it will usually have an even number of threads per inch.

Some online resources have diameters and tap size such as this Metric, Metric Fine, BSW, BSF, UNC, UNF and BA Thread Dimensions
It becomes more difficult to establish diameter when there are diameters of bolts and nuts - or dies and taps. The diameter of a tap is different to the diameter of its equivalent die.

 

[Joust]

All signs point to 7/8" x 14. Can ya dig it?

Arrived and fit.

Cheers