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Thread designations, locomotive whistle

Gears Phenom Gears Phenom
Gears Phenom

I've got this piece in front of me that is off a locomotives whistle which has threads I'm not familiar with. These are tapered threads, but these aren't any designation which I can find. I've been told perhaps "Bridge Taper Threads" or "Steam Boiler Threads". Only thing I know for certain is this is for Locomotives which have steam boilers. This isn't NPT or BSPT nor is it NPTF. The outside of the largest diameter part of the thread is measuring pretty much exactly 2.500". I'm being told that there are 12 threads per inch, though I can't really verify that as there isn't really a full inch of threads going on here.


Solid Edge 2019
Windows 7 Professional
Nvidia K2200 & Intel Xeon
"You're doing it wrong"

Re: Thread designations, locomotive whistle

Honored Contributor
Honored Contributor


Boilers use ASME that in turn uses ANSI specs for threads

ANSI has specs for most things like this, but you have to pay for the standards.


Measure the threads over 1/2" and x2


One other possibility is the threads dont match anything. Both items may have been made by hand.


Re: Thread designations, locomotive whistle


Vintage Steam power always warms a special place in my heart.


Do you know the origins of the locomotive?


could it be an M60X2.0T?

If you cannot find a Solid Edge setting, confirm you have a file open of the type that will be affected.

Re: Thread designations, locomotive whistle

If it is old train parts it is going to be 12 TPI 60deg with a 3/4" in 12" Taper.