# fittings for 1/16" or 3/32" copper tubing



## cfellows (Jun 6, 2010)

I'm beginning to research copper tubing fittings for attaching 1/16 or 3/32 copper tubing to my injection pumps and injectors on my hot bulb engine. anybody have any experience with fittings for tubing that small? Not sure whether it would be compression sleeves, flared, or what???

Chuck


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## stevehuckss396 (Jun 6, 2010)

I couldn't find anything when I was looking. I made some brass look-a-likes and soldered the tube in them. In my case I can still unscrew the threads and take things apart.


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## Blogwitch (Jun 6, 2010)

Chuck,

Here in the UK, because we have all the specialist sizes of threads already geared up for small pipe fittings (M.E., B.A.), we tend not to have the problems you do. 

Below 1/8" pipe size, we tend to make our own, consisting of a component union with a 60 degree taper (I use a centre drill for making the internal taper), a coned ferrule that the pipe is silver soldered into and a nut for tightening it all together. Just smaller versions of the 1/8" size. You can buy some fitting for 3/32", but not everyone stocks them.

This shows the system we tend to use. Go to pipe nuts and ferrules and single pipe unions.

http://www.steamfittings.co.uk/asp/index.asp

This downloadable catalogue from Bruce Engineering is very interesting, and again, shows what is available commercially. Start at about page 40 for steam fittings.

http://www.pollymodelengineering.co.uk/sections/bruce-engineering/docs/cat_may10.pdf

These might give you a few ideas on the way to proceed.


John


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## Stan (Jun 7, 2010)

I have never used 3/32" tubing but used lots of 1/16" SS with Swagelock fittings. I just took a quick look at their site and they make 1/16" in brass. Usual ordering info is to contact your dealer.I didn't look but there may be a dealer finder on the web site.

http://www.swagelok.com/downloads/webcatalogs/EN/MS-13-151.pdf


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## Cedge (Jun 7, 2010)

Just got my hands on some very small... .071 inch OD copper, called capillary tubing. Ten feet of it for $8.00 should last me a while. I've also seen 1 mm OD offered on the other side of the pond, but didn't order it. This will be used for oiler lines on engines. Fittings are non-existent so I'll have to figure a way to fake them. Any ideas?

Steve


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## cfellows (Jun 7, 2010)

Bogstandard  said:
			
		

> Chuck,
> 
> Here in the UK, because we have all the specialist sizes of threads already geared up for small pipe fittings (M.E., B.A.), we tend not to have the problems you do.
> 
> ...



Hey John, thanks for the links and the info. May have to think about how I would make some fittings. Small ferrules might be tricky. I may also just opt for 1/8" tubing since fittings seem to be readily available commercially.

Chuck


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## cfellows (Jun 7, 2010)

Cedge  said:
			
		

> Just got my hands on some very small... .071 inch OD copper, called capillary tubing. Ten feet of it for $8.00 should last me a while. I've also seen 1 mm OD offered on the other side of the pond, but didn't order it. This will be used for oiler lines on engines. Fittings are non-existent so I'll have to figure a way to fake them. Any ideas?
> 
> Steve



Yeah, I see that this is available on ebay in .071, .081 and .093 OD sizes. 

Chuck


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## Cedge (Jun 7, 2010)

Chuck
I got mine locally from, a supplier for the air conditioning and refrigeration repair trades. 

Steve


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## shred (Jun 7, 2010)

This article from the Gauge 0 guild might be useful-- they show a fitting for 1/16" OD tubing that looks relatively easy to make.

http://gauge0guild.com/manual/S9 - 6 - Small Repairs.pdf


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## Cedge (Jun 7, 2010)

Shed.... karma point for you. Exactly what I needed to see. gave me the insjght needed to do the trick... THANKS!!!!!

Steve


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## GWRdriver (Jun 7, 2010)

Chuck,
Per John's post above, . . . I like the British "nut & cone" connections which in our parlance are similar to pipe unions. They are similar to a flared connection but there is one more component. They are neat and strong although the female side of the connection needs to be fixed in something stationary so the nut can be tightened, or, there needs to be a hex applied to the female which adds a little bulk to the connection and then really does make it a union. 

View attachment UNIONS.tif


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## tel (Jun 7, 2010)

Yep, nut & cone connections are very easy to make, and very effective.

Here are some (l & r beside cylinder block) that I made for 1/16" piping on a multi-lubricator.


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## lordedmond (Jun 8, 2010)

tel

I have a need for info regarding 1/16 and 3/32 pipe fittings . please could you provide the sizes of the parts 

Thanks
Stuart


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## Blogwitch (Jun 8, 2010)

Chuck,

If you buy ready made hex bar, they are very easy to make. A centre drill takes care of the internal cone, and a 60 deg threading tool brought in nose on takes care of the male taper. 

If you get set up correctly, you can turn out dozens of them in no time.

If using brass, an ME carbon tap and die easily takes care of all the threading.

John


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## tel (Jun 8, 2010)

lordedmond  said:
			
		

> tel
> 
> I have a need for info regarding 1/16 and 3/32 pipe fittings . please could you provide the sizes of the parts
> 
> ...



OK Stuart. For 1/16" pipe I use a 1/8" thread (40 or 60 tpi). Make the nuts from 3/16" hex, frilled thru a loosish fit on 1/16" and drilled & tapped1/8" for 1/8 depth.

For 3/32 use a 5/32 tread, etc etc, 7/32 hex for the nut.


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## lordedmond (Jun 8, 2010)

Thanks tel


that will make them a bit big for my 5 inch loco the scale size looks like a 6BA hex , actually I need to make some for soma 54 thou pipe opps

last count up I will need about 40 or so plus ten for the floor

Stuart


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## deverett (Jun 8, 2010)

Stuart

You might like to consult the writings of Roy Amsbury in Model Engineer magazine (mid 1980s I would imagine). He produced beautiful scale fittings for 5" gauge locos.

Other writings you cold consider in the same journal are:
Mini Pipe Unions by A.A.T. Finn.         21 Jan 1983 pg 110
Making Union Nuts and Nipples by N. Bailey. 15 Feb 1985 pg 189

I could give you a scanned copy of these articles if you would like.

Dave
The Emerald Isle


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## lordedmond (Jun 8, 2010)

that would be very kind of you I will PM my email


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## cfellows (Aug 9, 2010)

Just a brief followup on my continuing adventures on the hot bulb engine, and, in particular, pipe fittings and connections for the fuel system. Following the link provided below, by Shred, I followed the guidelines for making a pipe flaring fixture. Instead of 1/16", I used 3/32 since I had that in copper and it seems more scale appropriate for what I'm doing. 

The flaring fixture is made from two pieces of 1/2" x 1/8" brass stock. I mounted them in my small vise, just as shown in the last picture, used a small center drill to start a hole and countersink it right on the joint where the two pieces met, then drilled the hole through with a #42 bit, which is about .003" smaller (in theory) than a 3/32. Then I separated the two pieces, sandwiched a piece of 3/32" tubing in the hole formed by the two pieces, and clamped it back together in my vise, with the tube about .010" proud of the fixture. 

I had ground a broken tap to a 30 degree (from the axis) point and I chucked this in my drill press. Next, I put a little oil on the end of the tube and on the 30 degree point. Using the slowest speed possible, I pressed down and slowly formed the flare on the end of the tube. The resulting diameter of the flare is about .130". Don't know if this is enough or not, but it was pretty easy to form and could probably be made somewhat bigger.
















Next, I gotta fabricate a nut with a matching flare.

Chuck


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## lordedmond (Aug 10, 2010)

further to my previous post on small fitting I have got the 1/16 and 3/32 one done

I made both the fittings from 6 BA brass hex stock the male part threaded 5/32 x 40 , then made the nut also threaded 5/32 x 40 with a 2.8 mm hole straight through

as 5/32 x 40 tapping size is 3.4 mm it leaves a shoulder 

the cone was made from 1/8 brass the outer turned down to 2.8 mm for 3 mm with the cone put on with a form tool in the rear tool post drill for pipe size the 3/32 ons are a bit thin but are ok

BTW the cove are best silver soldered with SS past just smear a tiny amount round the pipe cone joint heat the pipe and watch the joint flash round ,no chance of filling up the pipe this way

I had to make about 40 1/16 ones , sorry fro the mix of imp and metric but my drill set goes in 0.1mm steps ( 0.004 thou ) so getting the sizes right is much easier

stuart


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## cfellows (Aug 10, 2010)

Hey Stuart, got any pictures?

Thx... Chuck


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## lordedmond (Aug 10, 2010)

I will try and sort some out when I make the next batch 

but I may be able to get some pic of the completed ones 


Stuart


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## shred (Aug 11, 2010)

I'd guess that the leftover cone from drilling the hole for tapping would probably be sufficient on the nut side, though you might want to try and match the angles in high-pressure situations.


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## cfellows (Aug 11, 2010)

shred  said:
			
		

> I'd guess that the leftover cone from drilling the hole for tapping would probably be sufficient on the nut side, though you might want to try and match the angles in high-pressure situations.



Shred, could you elaborate? Not sure what you are saying here...


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## Blogwitch (Aug 11, 2010)

Chuck,

In all the flaring tools I have ever used, they were never just a cone shape.

Usually they had three or four flats on the cone, like an upside down pyramid with rounded corners.

It was to do with gently stretching the metal, rather than just deforming it in one go. They would even flare stainless tubing beautifully. You would feed in a little, then turn the former, feed in a bit more and turn again until you had the flare perfectly formed. I am sure it has something to do with not putting too much stress into the flare to a point where it would split.

I am sure a few of the aircraft lads on here have done a fair few flares in their time, flared joints were standard hydraulic practice on aircraft.


John


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## Dan Rowe (Aug 11, 2010)

Chuck,
I think Shred is talking about the union nut for the flared tube. It seams to me that a counter sink with the same angle as the one to drill the inital hole in the forming plates would work fine.

That is most likely the plan you were going to use. I think that a set of pins fixed on one side would make the forming plates line up and simpler to put in the vice.

Nice work I like the idea and it is in my mental sketch book.

Dan


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## Dan Rowe (Aug 11, 2010)

John,
I have never seen the tool you are refering to but I think I am following the concept.

The best type of flair tool I have ever used it the one made by Rigid. Here is a cataloge quote about the key feature of the design:

"Hardened steel flaring cone, eccentrically mounted in needle bearings, produces rolling action for even metal flow, giving uniform flare walls without galling."

This is the tool I bought for my shop.
http://www.ridgid.com/Tools/458R-Ratchet-Flaring-Tool/EN/index.htm

Dan


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## Blogwitch (Aug 11, 2010)

Sorry Chuck about doing a bit of hijacking, but this is just to show Dan what I am on about.

If you see the real rough C-o-C at the bottom, it should roughly explain what I was on about.

I suppose, the rolling action of the one you showed does the same as the spreading action of my flairing tip. Gently rolling and spreading the material to prevent stress cracks.


John


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## shred (Aug 11, 2010)

Dan Rowe  said:
			
		

> Chuck,
> I think Shred is talking about the union nut for the flared tube. It seams to me that a counter sink with the same angle as the one to drill the inital hole in the forming plates would work fine.


Yeah, I was thinking that the remnant of the hole-forming prior to tapping would have a coned end were it drilled (see C-O-C). An appropriately-sized center drill would provide the nicest angle, but might not be easily obtainable.


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## cfellows (Aug 11, 2010)

Bogstandard  said:
			
		

> Sorry Chuck about doing a bit of hijacking, but this is just to show Dan what I am on about.
> 
> If you see the real rough C-o-C at the bottom, it should roughly explain what I was on about.
> 
> ...



Thanks, John, doesn't look like it would be too hard to make something like that. Actually, I could probably just mill some shallow flats on the pointed tool I used and get the same affect. When I tapered the tube shown further down this thread, it was done with the drill press turning on it's slowest spped.

Chuck


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## jirik92 (Aug 11, 2010)

I have used similar princip a few years ago (see my pages http://www.steamer.cz/par_fit.html). But while years I have problem - pipes damaged while many times join was assembled/dissassembled. I returned to other princip - soldered conus on pipe- see picture.
Regards, Jiri


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## shred (Aug 11, 2010)

jirik92  said:
			
		

> I have used similar princip a few years ago (see my pages http://www.steamer.cz/par_fit.html). But while years I have problem - pipes damaged while many times join was assembled/dissassembled. I returned to other princip - soldered conus on pipe- see picture.
> Regards, Jiri



Nice idea! One more for the notebook. Looks pretty easy to manufacture as well. Thanks


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