British Straight Thread Fittings

[briankenyn]

Hi All,
I'm new to the group and working on a small steam shutoff valve and lubricator. The design came from a book by TD Walshaw who wrote under the pen name Tubal Caine. The fitting calls for a 1/4- 40 nut and a 60deg. inverted cone in the spigot, but I am unable to figure out how the tubing will flare or seal.
Has anyone any familiarity with this approach?

Thanks,
Brian

 

[Kermit]

Have you seen this post yet?

http://www.homemodelenginemachinist.com/index.php?topic=10310.0 It might give you some idears.

AND welcome to HMEM,
Kermit

Edit: After reading your question again, I think I confused the subject. You don't need to work on the safety valve, but on the connection TO the safety valve>

DOH!

lathe dead centers are 60 degree angle. Aren't they?

 

[Maryak]

Brian,

Welcome to our forum. wEc1 Please post a little about yourself and your interests in our welcome section.

I can't quite visualise what you're asking so perhaps a sketch so we can try and help you.

Best Regards
Bob

 

[briankenyn]

Thanks for the help and sorry for the confusion.
The spigot is a male fitting threaded 1/4 40 and silver soldered into a 5/16" square brass valve body. The spigot is drilled through 3/32" into the valve chamber, and the author suggests using a 60deg center drill to flare the front inside of the spigot where the nut would meet. Copper tubing is connected through a 1/4 40 threaded nut and screws on to the spigot, but the plan doesn't indicate how the tubing is gripped by the nut or how it seals when tightened on the spigot. I am not sure that my drawing skills will improve on this picture. My experience with copper tubing from years ago used a reverse approach, where the copper was flared outwardly and compressed against the fitting by the nut. I hope that helps a little.
Thanks,
Brian

 

[Blogwitch]

Brian.

I think Tubal Cain designed it for fitting as shown in the C-o-C below.

This is a standard type of steam fitting in the UK, and you can buy small packs of ready made ferrules and nuts. The more experienced amongst us usually make them up ourselves.

I hope this clears it up for you.

If you need more info, I can take a shot of a real life one, and find you a source to buy them.


Bogs

 

[SBWHART]

Welcome Brian

You solder a coned nipple to the pipe, and screw down onto the nipple with a union nut, like these her https://maccmodels.co.uk/index.php?cPath=46_225&osCsid=21d1447d79f7189c3a274fc72a87a1f4

The coned nipple seals into the female cone in the fitting.

I've just done some pipe work for my loco boiler test rig using this system when I go out into my shop later this morning I'll take some pics.

Stew

 

[tel]

I make 'em the same as Bogs, but omit the tail on the olive.

 

[SBWHART]

Her we go

I've think we've got it sorted between us.

The nipples are soft soldered onto the pipe, one tip don't forget to put the nut on the pipe before you solder the nipple, Don't ask :big:

Stew

 

[briankenyn]

That's it exactly!!
Many thanks to you all for your kind responses. I'll probably try to turn the olive myself, now that you have pointed the way. Now that I understand the process, I find myself wondering if I shouldn't later skip a step, reverse the male/female design and use a simple tube flair.
Thanks again-I'm very glad to be here. It is heartwarming to openly share in the knowledge of so many talented people here and halfway 'round the world!

Brian

 

[steamboatmodel]

Stew posted it before me,
"The nipples are soft soldered onto the pipe, one tip don't forget to put the nut on the pipe before you solder the nipple, Don't ask"
I usually Silver solder mine though.
Regards,
Gerald.