What are these fittings called?

I need to buy a few tubing fittings similar to those shown in this photo, but my search for them is
considerably hampered by not knowing what they're called. Any help would be appreciated.
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The purpose is to make a temporary butt joint between the end of one tube and the side of
another, by attaching with a screw.
Reply to
Doug Miller
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Doug Miller fired this volley in news:XnsA38479B16993Bdougmilmaccom@78.46.70.116:
Those are not "tube fittings". They're mechanical adaptors that are probably custom-made by the company making the chair/table/tent/whatever into which they assemble.
They are called "plastic aluminum tube joiners".
What were they part of? The manufacturer of the original device is probably the best source for them.
Lloyd
Reply to
Lloyd E. Sponenburgh
I've never seen a name for them. It looks like something from a medical mobility assistance device.
For temporary use would chain link fence post tee joint clamps work? The smallest size is 1.315" top rail, called "1-3/8."
A fence company would have a much better selection than the big-box stores.
-jsw
Reply to
Jim Wilkins
You could make one similar to a diagonally split bicycle handlebar stem: -jsw
Reply to
Jim Wilkins
Radius tube connectors here
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Reply to
David Billington
Easy enough to make with a milling machine or drill press. Nylon bar stock, drill the peice in half to form the coped end, then drill and tap center.
Reply to
clare
Doug Miller wrote in news:XnsA38479B16993Bdougmilmaccom@78.46.70.116:
"radius tube connectors"
Reply to
Ian Malcolm
Ian Malcolm wrote in news:XnsA384C521C15AF0xDEADBEEF@78.46.70.116:
Thanks to all who replied. I think this will put me on the right track.
Yes, I could get them from the manufacturer of the parts in the photo, but I need them sooner than I'm likely to get them that way. If I can't find a local source, I need to make my own.
Fence-post fittings are too large; the tubing in the photo is 7/8" OD.
Reply to
Doug Miller
Or use neoprene rubber "well nuts"
Reply to
Shed_Fiddler
but I need them sooner
I need to make my own.
Looks like pretty thin wall. Maybe force a 7/8 OD wooden dowel into it?
Reply to
Guv Bob
"Guv Bob" wrote in news:NO- dnU73vYRZGnTOnZ2dnUVZ snipped-for-privacy@earthlink.com:
[...]
Force a 7/8 OD wooden dowel inside a 7/8 OD aluminum tube?
Yes, the wall is pretty thin, but it's not zero. Somehow, I don't think that's going to work very well.
Reply to
Doug Miller
Heating the aluminum tube might expand it more than the thickness of the metal. If so a hot tube might swallow a dowel and cool skin tight.
Martin
Reply to
Martin Eastburn
Martin Eastburn wrote in news:PUzGv.194874$ne6.53439 @fx09.iad:
No, it won't. Aluminum expands about 12 parts per million per degree Fahrenheit. It would have to be heated to over 800 degrees F to increase the ID by just 1% -- and that's not nearly enough to make the ID as large as the room-temperature OD.
We won't even talk about what that would do to the wooden dowel...
Reply to
Doug Miller
What type of expansion is that? Volume ?
Try linear expansion. around the circle. It is a long ring. A ring will expand more.
Think wagon wheel expanding the wheel band in a fire and then sliding it onto the oak frame of the wheel. cool with water and it fits tight.
one of the experiments in thermo labs is to take a ring and a ball that have the same outsides. Heat both in a flame and the ball slides easily through the ring. Volume is less than linear of the ring.
Martin
Reply to
Martin Eastburn
Martin Eastburn wrote in news:EYAGv.230786$ snipped-for-privacy@fx05.iad:
No, linear expansion.
No, it will not. The diameter and the circumference increase by exactly the same proportion.
Related thought experiment: suppose you have a string wrapped tightly around the surface of the earth. How much longer does that string need to be, if you want to put it on one-foot-high standoffs all around the planet?
I understand how that works. Do you understand that it's not *at all* the same situation? Fitting a steel band over an oaken wagon wheel requires only that the ID of the band is less than the OD of the wheel at ambient temperature but greater than the OD of the *wheel* when heated -- *not* that the ID of the band when heated exceeds the OD of the *band* at ambient.
Do the calculations. Assume an aluminum tube with 0.875" OD, 0.050" walls, and therefore 0.775" ID, at 75 deg F. To what temperature must the tube be heated to increase its ID to 0.875"?
Reply to
Doug Miller
...
... About 8" (two feet / pi).
Related thought experiment: Suppose you have a mile of railroad track. Supp ose it gets really hot and the track expands (in length) by one inch. Suppo se that, due to the expansion, the track buckles in the middle, forming an isosceles triangle. How high will the bump in the middle be?
Reply to
rangerssuck
Uh, that's two feet *times* pi.
Reply to
Ed Huntress
...
C2=pi*D2; C1=pi*D1 --> C2-C1=pi*(D2-D1) = 2*pi ft
Reply to
dpb
yeah, well, haven't finished the morning coffee yet. Besides, by the time t hey finished building all those little standoffs, I'd have been paid and sp ent the money. So sue me ;-) And it's all a trick question anyway: EVERYONE knows the earth is flat.
uppose it gets really hot and the track expands (in length) by one inch. Su ppose that, due to the expansion, the track buckles in the middle, forming an isosceles triangle. How high will the bump in the middle be?
Reply to
rangerssuck
Don't forget that the string will stretch. And there is the catenary curve droop of the string *between* the standoffs. Those two factors work against each other.
Are we having fun yet? d8-)
Reply to
Ed Huntress

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