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Author Topic: Mamod steam engine SE2 relief valve thread size  (Read 2466 times)

boaterjim

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Mamod steam engine SE2 relief valve thread size
« on: July 26, 2022, 03:05:20 pm »
Hiya steamers, can anyone out there please tell me the thread size and type of a Mamod SE 2 or 3, steam engine relief valve?
It seems to be given as 3/8, but its not 3/8 BSF as that is the same size of course fishing gear bank sticks and landing net fittings, and they do not fit.
 So is it in fact 3/8 and what thread?


Thanks a confused steamer,


Jim sunny Gainsborough
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SteamboatPhil

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Re: Mamod steam engine SE2 relief valve thread size
« Reply #1 on: July 26, 2022, 06:54:44 pm »
3/8 seems big, most mammon used 1/4 BSF, if it is 3/8 it will be 3/8 x 26 BSB (or BSP they are close)
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boaterjim

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Re: Mamod steam engine SE2 relief valve thread size
« Reply #2 on: July 28, 2022, 08:35:01 am »
Hello Phill, thanks for your reply, a 3/8 bsf nearly fits but the thread is wrong, 1/4 seems to be the normal size for most of the models, except the early relief valves. What is BSB not heard of that one before, the other i take it is British standard pipe bsp.
thanks again
Jim
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SteamboatPhil

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Re: Mamod steam engine SE2 relief valve thread size
« Reply #3 on: July 28, 2022, 10:15:23 am »
Hi Jim
Yes BSP is British standard pipe, BSB is British standard Brass
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Circlip

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Re: Mamod steam engine SE2 relief valve thread size
« Reply #4 on: July 28, 2022, 11:34:15 am »
Hardly think 3/8" BSP., Tapping size drill for that is 16mm O0


  Regards  Ian.
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John W E

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Re: Mamod steam engine SE2 relief valve thread size
« Reply #5 on: July 28, 2022, 04:09:12 pm »
just checked the thread on the Mamod safety valve.   Admittedly, the diameter is 1/4 inch, but, I checked it with a thread gauge and the threads are 26 tpi.


When I have checked on the web - cos to me it is an oddball thread - it works out to be a cycle thread used by the cyclists industry.


I know the thread you are looking at is 3/8 diameter but, this Mamod being an 'old' English Company - I am wondering if it is 3/8 cycle thread.  The other thing which came  to me the thread on the 1/4 diameter was very close to the pitch and size of the O/BA thread.


That has just thrown a cat among the pigeons :-)


I know there is a guy on EBay who I have dealt with in the past does a lot of spares for the Mamod steam engines - because he supplied me with a washer for my Meccano steam engine.


John
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boaterjim

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Re: Mamod steam engine SE2 relief valve thread size
« Reply #6 on: July 28, 2022, 10:57:25 pm »
Hi guys well i never knew or ever heard of BSB or cycle thread before. So im of to ye old bike shop tomorrow,
 I wonder if the thread is the same type as the old wheel inflation point on yer old type bike wheel ?


Any one thought it might be UNF thread?


If I was still at work we used to have a massive Gash box of nuts/bolt etc you could go to and usually find what you wanted in it, but most stuff seems to have gone metric.  :}
jim
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chas

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Re: Mamod steam engine SE2 relief valve thread size
« Reply #7 on: July 29, 2022, 08:46:23 am »
Have you tried contacting Tony Green steam models? They're long established suppliers of most things and knowledge to do with Mamod.
 
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boaterjim

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Re: Mamod steam engine SE2 relief valve thread size
« Reply #8 on: July 31, 2022, 08:36:31 am »
Hello again, ended up on Saturday at the car garage and got me a mail and female brake pipe union and variose bolts and set screws.
Results are the safety valve is a very loose fit into the union, and the mail part of the union does not fit into the engine, so it aint BSB or BSP nor is it whitworth and not BSF.
Biker grove shop next week, may even buy a set of thread gauges  <:(
Jim
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boaterjim

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Re: Mamod steam engine SE2 relief valve thread size
« Reply #9 on: August 08, 2022, 06:24:57 am »
Hi all , so in the end I can say the Mamod safety valve is 3/8 BSF  :-))
Mine was not  >>:-( I can only assume that at some time its been damaged changed ???
Now sorted, thanks for all of your inputs,
regards
 Jim
[size=78%] [/size]

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