Connecting 1/4 copper pipe & fittings

[Mick]

Hi,

I am looking to use this type of globe valve with similar type “T” connectors also with ¼ x 40 female thread for a Stuart steam engine.

http://cgi.ebay.com/Globe-Valve-B...faultDomain_0?hash=item5180ea8acc

If I thread a ¼ copper tube with a ¼ x 40mm die can I screw it into this valve and get a proper fitting or do I need anything else?

Thanks for any advice.

Cheers Mick

 

[Tin Falcon]

mick:
imo you should probly not try to thred copper tubing. brass is usualy used for piping . the threads on the copper may not be strong enough to hold.
Tin

 

[Mainer]

I guess I'm a little more optimistic than Tin. I don't think strength will be an issue, but on the other hand I think you might have trouble getting a die to cut a clean thread in copper. A trial will soon resolve that, however. (I assume the "mm" part of your thread spec is a typo....)

As far as needing anything else, I doubt it. A little pipe dope (the goopy kind) wouldn't hurt, I suppose, but I might try it dry first and see what happens.

All this assumes the pressures involved will be "low" (10-15 psi).

 

[bearcar1]

I cannot seem to get the link to open properly to view the fitting in question, but if I may suggest that a brass ferrule/adapter be turned up, one that can be sufficiently tightened into the fitting and a pipe union hard soldered to that to facilitate removal. Threading copper tubing/pipe is quite an undertaking. Using an adapter as mentioned or the threading of brass piping would be the best bet.

BC1
Jim

 

[Mick]

Thanks for the feedback, yes the mm was a typo.
The maximum recommended pressure for the Stuart boiler and engine I have is 60psi but from running it I cannot imagine actually getting to that pressure and usually keep within the bounds of 0 to 15 psi.

I hope to hook the engine up to a pump or dynamo later on so the pressures to run it may increases but I will then look at beefing up connections where necessary.

Cheers Mick

 

[Cedge]

The coolant lines on the recent Victorian project were made of threaded 1/4 inch copper tubing. The first efforts were rather "iffy" at best when trying 1/4- 28 threads. I finally had full success using a 1/4 -32 die. The stuff will thread ok, but it is gummy when you begin and it work hardens as things progress.

Steve

 

[tel]

It's not the easiest thing in the world to thread, but 40tpi ME dies will do the job as long as you apply Trefolex freely and back the die off often. Strength is not really an issue - I threaded copper for the steam tee on a couple of locos with no issues

 

[bentprop]

I seem to remember reading somewhere that milk is an ideal lubricant for copper.
I presume you would need the full-fat variety,not that wimpy low-fat stuff :big:

 

[rleete]

It's the fat, so heavy cream is best. Woe to the guy who doesn't clean up well afterwards - the smell will floor ya!

Crisco or lard is another option. I had reasonable success with it; it doesn't make quite so much of a mess, and no smell if you don't get every last bit cleaned up.

No matter what, copper is a real pain.

 

[Mick]

I used a drop of engine oil to lub the tap. Is this not as good s fat or a proper solution?

 

[rleete]

It should work. With copper, you have to be very careful to constantly reverse the tap to break the chips. It tends to "smoosh" (technical term) off, rather than breaking a clean chip off.

 

[tel]

I seem to remember reading somewhere that milk is an ideal lubricant for copper.
I presume you would need the full-fat variety,not that wimpy low-fat stuff :big:

But 'ow do you get the cow to stand quietly by the lathe while you do this? At least a tin of Trefolex doesn't run away.