Union copper tube to 1/4-40 MTP ?

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DianneB
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Union copper tube to 1/4-40 MTP ?

Post by DianneB » Mon May 07, 2018 5:48 pm

Has anybody seen a supplier of unions with 1/4 copper tube on one side and 1/4-40 MTP on the other?

Thanks!

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FLSTEAM
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Re: Union copper tube to 1/4-40 MTP ?

Post by FLSTEAM » Mon May 07, 2018 6:06 pm

Just drill out one side of the threaded union and sweat solder to your copper tube.

John B.
http://www.ngshay.com/
Shay drawings and castings

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Builder01
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Re: Union copper tube to 1/4-40 MTP ?

Post by Builder01 » Mon May 07, 2018 6:45 pm

PM research makes them, but, only for up to 3/16" tube. It would be quicker to make your own anyway than to order one even if they made one in the size you needed.

David

jtdute
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Re: Union copper tube to 1/4-40 MTP ?

Post by jtdute » Mon May 07, 2018 7:35 pm

LocoParts has the union adapters in the size you are looking for, plus various other sizes.

jtdute
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Re: Union copper tube to 1/4-40 MTP ?

Post by jtdute » Mon May 07, 2018 7:38 pm

I should have also stated that LocoParts has slightly changed design of out unions. Now the MTP unions and the silver solder unions are now interchangeable. You an have silver solder connection on one side and MTP thread on the other. The union Adapters have male thread on the one end.

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DianneB
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Re: Union copper tube to 1/4-40 MTP ?

Post by DianneB » Tue May 08, 2018 6:04 am

That's good to know Thanks!

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Fred_V
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Re: Union copper tube to 1/4-40 MTP ?

Post by Fred_V » Tue May 08, 2018 7:43 am

once you get comfortable making fittings a whole new world opens up to you. Anything you need can be made in a few minutes. I can make a 1/8 to 1/4 pipe reducer bushing faster than I can drive one way to Home Depot. I have CAD drawings for all sizes of unions and they can be adapted on either end for whatever I need.
Fred V
Pensacola, Fl.

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DianneB
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Re: Union copper tube to 1/4-40 MTP ?

Post by DianneB » Tue May 08, 2018 11:30 am

IWISH I could make nice fittings like unions but I am either not a good enough machinist or my machine tools are too old! I just can't get the precision needed.

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Builder01
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Re: Union copper tube to 1/4-40 MTP ?

Post by Builder01 » Tue May 08, 2018 2:54 pm

It's actually not too hard to make cone unions. I made all of the fittings for my loco. There are only a few diameters that need to be turned, and they are not very critical. A "how to" for this sounds like something I should add to my website. Off to the shop with my camera!

David

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DianneB
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Re: Union copper tube to 1/4-40 MTP ?

Post by DianneB » Tue May 08, 2018 4:16 pm

Good for you David! (I need all the help I can get LOL!)

RET
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Re: Union copper tube to 1/4-40 MTP ?

Post by RET » Tue May 08, 2018 7:37 pm

Hi Dianne,

I make all my fittings and once you get the hang of it, its pretty easy. I use collets to hold the fitting in the lathe which helps a lot in keeping everything true and lined up properly. By making my own fittings, I can go down one wrench size over the commercial fittings and still have the same bore so the completed fitting looks more to scale, especially when you are working in 3 1/2" gauge.

Most of my connections are simple, you make the "socket" for the ball end with a center drill with the threads on the outside and the nut has a stepped inside to pull the shoulder on the ball into the socket. This kind of connection can be made and unmade as many times as you want. The ball end/sleeve combination is simply silver soldered onto the end of (in my case) thin wall stainless tubing which you bend to suit. If you need really sharp bends, use Cerrobend to fill the tubing since it melts below the boiling point of water. Its a bit of a pain, but melt and use the Cerrobend under water for safety (its an alloy of lead & other low melting point metals so you don't want to get it too hot).

I use national fine taps for the nuts, but since I have all the M.E. taps & dies (both 32 and 40 tpi.) as well, I could use them just as easily.

I hope this helps a bit.

Richard Trounce.

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Builder01
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Re: Union copper tube to 1/4-40 MTP ?

Post by Builder01 » Tue May 08, 2018 10:39 pm

Hi Dianne,

I pretty much do as Richard has described including the Cerrobend method for tight bends. Also, I have just finished a page on my web site that shows pictorially what is involved in making cone unions. The parts you see in the photos I just made tonight for the new page. it took much longer to make the web page describing how to make them! Here's the link:

https://supersimplex.yolasite.com/How-t ... -Union.php

For a PDF copy of my Cone Union Specification, scroll all the way to the bottom of the page and right click on the large button.

Also, here's a photo of some of my other unions and piping using the same techniques.
DSCN1704 - resized.jpg
David

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