Hi All,

I need a 4-feet (each) of telescoping square tube around 1" to 1-1/2"
square. The actual sizes are not important as long as they telescope
easily and the smallest tube needs to be at least 1" square.

I need 16G steel at a minimum for both inner and outer tubes.

It does not need to be a precision sliding fit, just a good close fit.

I have done some online searching but have only found bulk suppliers.

I checked with a few online metal suppliers but they would not
guarantee any of their tubes for telescoping.

If I can't get square tubing then I may have to settle for round and
use through-pins to keep them aligned.

Any suggestions for EITHER/BOTH square or round tube suppliers?

Thanks

Dave

"Dave, I can't do that" wrote in message
...
Hi All,

I need a 4-feet (each) of telescoping square tube around 1" to 1-1/2"
square. The actual sizes are not important as long as they telescope
easily and the smallest tube needs to be at least 1" square.

I need 16G steel at a minimum for both inner and outer tubes.

It does not need to be a precision sliding fit, just a good close fit.

I have done some online searching but have only found bulk suppliers.

I checked with a few online metal suppliers but they would not
guarantee any of their tubes for telescoping.

If I can't get square tubing then I may have to settle for round and
use through-pins to keep them aligned.

Any suggestions for EITHER/BOTH square or round tube suppliers?

Thanks

Dave

Plenty of places listed for Telespar and Telestrut but not sure if that
meets your needs or the minimum order

"Dave, I can't do that" wrote in message
...
Hi All,

I need a 4-feet (each) of telescoping square tube around 1" to 1-1/2"
square. The actual sizes are not important as long as they telescope
easily and the smallest tube needs to be at least 1" square.

I need 16G steel at a minimum for both inner and outer tubes.

It does not need to be a precision sliding fit, just a good close fit.

I have done some online searching but have only found bulk suppliers.

I checked with a few online metal suppliers but they would not
guarantee any of their tubes for telescoping.

If I can't get square tubing then I may have to settle for round and
use through-pins to keep them aligned.

Any suggestions for EITHER/BOTH square or round tube suppliers?

Standard Tube Sales in Mass. has a huge inventory of this stuff. You would
proly have to buy a full length tho, they'd cut it, ship it ups, and bang
you hard -- but proly not as hard as McM.
Standard Tube is a bunch of cocksuckers, but they do have inventory.

You might could luck out at HD, tho.

But here's the pro'leng:
As someone mentioned, 12 ga 1 1/4 would proly do, depending on the size of
the inside flash, which can be substantial. In which case you might have to
go with 13 or 14 ga.
Often, tho, that flash is not on a vertical centerline, and if the inside
tube is round, the flash is moot, for an easy solution.

Also, you have to make sure the outside radius of the corners of the inner
square tube are compatible (will clear) the inside radius of the outside
tube, which also argues for making the inside tube round.

And mebbe you can come up with a design so that a rotating inside tube is
acceptable -- this can sometimes actually simplify the overall design. You
could also weld tabs to the round tube so that it does not rotate, or weld a
short pc of sq tube to it that has clearance for the flash, etc.
Or run pins through the round pc that ride on the diagonal of the inside
larger tube. Two of these pins at 90 deg should constrain the inner round
tube nicely.

Another thing you can do is use available square tubing with a sloppy fit,
plug the inside tube with some solid material, drill/tap it, and use set
screws to take up the slop. iow, the set screws will ride on the inner
walls of the outside tube, and make for a nice fit/feel. You'll need 1
screw for each face, at two different points along the length.

If you do this, don't be tempted by symmetry to put the set screws on the
centerline of the inside tube, but rather as close to a corner as you can,
which will minimize any internal cocking/camming. If this is not
intuitively clear, it will be if you put the screws along the centerline.

--
EA




Thanks

Dave

"DT" wrote in message
...
In article
,
says...
Hi All,

I need a 4-feet (each) of telescoping square tube around 1" to 1-1/2"
square. The actual sizes are not important as long as they telescope
easily and the smallest tube needs to be at least 1" square.

I need 16G steel at a minimum for both inner and outer tubes.


McMaster-Carr carries it, search for "nestable tubing". The smallest
sizes is 1 1/2" square, 12 gauge, perforated or solid. They have 48"
lengths.

--
DT

I wonder what the tolerances, or slop is. On typical steel 1" .065" square
tube, the next smaller size is .75". Therefore, I figure the slop to be:
1" - .065 - .065 -.75" = .12 16 ga is .0625".

..12 divided by 2 = .6, so there is about one whole wall thickness of space
around the .75 tube. On all the tubing ornamental metal I have built, it is
a workable fit, but too sloppy to be used for much of anything that requires
a real sliding of telescoping pieces, such as an antenna, unless you have a
bit of length of one tubing that stays inside another. If you want to
telescope anything and have it straight at all, you have to shim it, or weld
it using a straightedge, then do rosette welds along it through drilled
holes to make it stable. Just wondering if the tube you mention is trimmed
flat on the inside, and what the "slop" factor is.

On such things as telescoping antenna, I wonder what those tolerances are,
and if square tube of that minimal of tolerances can be purchased. I would
think so, as most anything that can be thought of can be produced. I just
wonder about the cost.

Steve

On Feb 16, 2:51*am, "Dave, I can't do that"
wrote:
Hi All,

I need a 4-feet (each) of telescoping square tube around 1" to 1-1/2"
square. The actual sizes are not important as long as they telescope
easily and the smallest tube needs to be at least 1" square.

I need 16G steel at a minimum for both inner and outer tubes.

It does not need to be a precision sliding fit, just a good close fit.

I have done some online searching but have only found bulk suppliers.

I checked with a few online metal suppliers but they would not
guarantee any of their tubes for telescoping.

If I can't get square tubing then I may have to settle for round and
use through-pins to keep them aligned.

Any suggestions for EITHER/BOTH square or round tube suppliers?

Thanks

Dave

Excuse me for being a bit thick, but have you tried looking in the
phone book and ringing up steel merchants?

Andrew VK3BFA.

On Tue, 15 Feb 2011 21:45:56 -0800, "Steve B"
wrote:


"DT" wrote in message
...
In article
,
says...
Hi All,

I need a 4-feet (each) of telescoping square tube around 1" to 1-1/2"
square. The actual sizes are not important as long as they telescope
easily and the smallest tube needs to be at least 1" square.

I need 16G steel at a minimum for both inner and outer tubes.


McMaster-Carr carries it, search for "nestable tubing". The smallest
sizes is 1 1/2" square, 12 gauge, perforated or solid. They have 48"
lengths.

--
DT

I wonder what the tolerances, or slop is. On typical steel 1" .065" square
tube, the next smaller size is .75". Therefore, I figure the slop to be:
1" - .065 - .065 -.75" = .12 16 ga is .0625".

.12 divided by 2 = .6, so there is about one whole wall thickness of space
around the .75 tube. On all the tubing ornamental metal I have built, it is
a workable fit, but too sloppy to be used for much of anything that requires
a real sliding of telescoping pieces, such as an antenna, unless you have a
bit of length of one tubing that stays inside another. If you want to
telescope anything and have it straight at all, you have to shim it, or weld
it using a straightedge, then do rosette welds along it through drilled
holes to make it stable. Just wondering if the tube you mention is trimmed
flat on the inside, and what the "slop" factor is.

On such things as telescoping antenna, I wonder what those tolerances are,
and if square tube of that minimal of tolerances can be purchased. I would
think so, as most anything that can be thought of can be produced. I just
wonder about the cost.

Steve

Certainly the telescoping legs on a large camera tripod are bushed and
things like the telescoping boom brace on a boat are the same. I
suspect that tubing with the required clearance to telescope without
shimming or bushing would be something special.

In article ,
says...
"DT" wrote in message
...
In article
,
says...
Hi All,

I need a 4-feet (each) of telescoping square tube around 1" to 1-1/2"
square. The actual sizes are not important as long as they telescope
easily and the smallest tube needs to be at least 1" square.

I need 16G steel at a minimum for both inner and outer tubes.


McMaster-Carr carries it, search for "nestable tubing". The smallest
sizes is 1 1/2" square, 12 gauge, perforated or solid. They have 48"
length.


I wonder what the tolerances, or slop is.


Well, the tubing from McMaster-Carr is designed as a nestable system.
Each tube is 1/4" larger than the next. The wall thickness is .105",
therefore there is .020" clearance. Since it is designed to nest there
are no interferring welds.

--
DT

Thanks DT,

The "nestable" word has provided many more options to explore.

Dave

On 2011-02-16, john B wrote:

[ ... ]

Certainly the telescoping legs on a large camera tripod are bushed and
things like the telescoping boom brace on a boat are the same. I
suspect that tubing with the required clearance to telescope without
shimming or bushing would be something special.

However -- the telescoping tubing used on the typical hydraulic
engine host is not bushed. How tight a tolerance do you need? In the
case of the engine hoist, the necessary length overlap for strength
minimizes the slop.

Enjoy,
DoN.

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