Does this Thread Size sound familiar?

[Stevekane]

Hi, nothing to do with woodwork but I I think there are a number of people on here well versed in thread sizes and types.
The O/D is said to be 1.3/8ins with a pitch of 16tpi. To put it into context its a blanking plug on a bronze valve which I think will be Swedish made. The plug is designed to be periodically removed and is sealed with a rubber washer. Anyone any ideas what the thread might be?
Steve.

 

[dickm]

If it's Swedish, would expect it to be metric, not imperial, but could be wrong. Will go and consult Mr Zeuss.
Update: it appears to be 1 3/8"UNF. See Unified Thread Series 16 TPI ANSI/ASME B1.1

 

[Stevekane]

Many thanks indeed Dick, thats really helpful, to quote from the Zeuss description “16-UN - Unified Extra Fine Thread, which is used for special purposes.The thread angle is 60°.”
I felt that it was a fine thread, maybe they used that to make it a bit more water tight? Now my next challenge is trying to find something that size that will screw into it. This is a valve on a little boat I have and once or twice a year I have to remove the bronze plug and stick a hose into the hole to flush the engine through, its easy to end up tipping a load of water into the engine compartment! So my idea was I might be able to find somthing that would screw into it and I could then adapt that to take a hose fitting,,I was hoping that it would be something I might find in a plumbers merchants which seems unlikly? But at least I now know what thread to look for, so many thanks indeed.
Steve.

 

[baldkev]

I have recently had a lathe backplate drilled and threaded. I would imagine if you find a high quality engineering firm, they will be able to make a fitting up for you..... might cost a bit, my backplate cost 50 quid to thread

 

[John Hall]

Would it be easier to drill and tap a smaller hole into the plug to take some form of tap fitting that would accept a garden hose connector or something similar