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View Full Version : Swaging Out Square Tube..... Thoughts !



JoeLee
12-17-2010, 11:00 AM
Back in Sept. I posted some info on some 2 1/4" sq. telescopic tube I bought from a supply house that was not square. Anyway, they sent me a piece that was acceptable and I returned to the project. The 2 1/4" sq. tube fits perfectly over the 2" sq tube with just enought clearance as it should. How ever, after welding the gussets to the side of the 2 1/4" tube the 2" no longer fits inside. I had a feeling that welding to the 2 1/4" would play out this way as it always does. Looking at the pictures you can see where I started to file the inside of the tube where it's binding. I know I can get it to fit again by filing but thats really time consuming. So.......... the $50 question here is can I swage the tube out to open it up enough to fit again. My thought is to make a 2" square die, tolerance it a few thou over the measured size of the 2" tube that I have to go into it, radius the edges, polish it up a bit and with some oil press it through the 2 1/4" piece with hopes that it will expand it just enough to make it fit again. I know the die should be hardened to eliminate the chance of galling as it's pressed through but I'm just wondering aprox. how much over size I should make the die as compared to the OD of the 2" tube. I'de hate to fall short by a couple thou and have to make another die, and I still have to weld down the sides of the gusset wich will only add to the problem. Any one have any idea on what to expect here??

JL.........................

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Lew Hartswick
12-17-2010, 11:14 AM
I'm not a weldor (sp?): But how about some form of a "backing" inside
the corner, or the whole peice, of 2 1/4 tubing while doing the job?
...lew...

Davo J
12-17-2010, 11:28 AM
That would be a good job for one of those little air belt sanders, they only have a 10mm (3/8) wide belt.

Dave

strokersix
12-17-2010, 11:55 AM
Stand a steel triangular block up on your anvil, or the floor. Place your part over the block so the angled side faces the area you wish to push out and the vertical side is against the opposite wall. Take a piece of steel bar, say 1/2 x 1 inch and drive it into the wedge, forcing the deformed area out. This will concentrate the force in local area and push it out a little at a time. I would try about 15 degrees on the wedge angle.

japcas
12-17-2010, 12:06 PM
JoeLee, how about making 2 tapered wedges that look like adjustable parallels that are narrower than the tubing. Then you can press on one of them to push the sides out, and depending on how much you press, the size is adjustable. This way you don't have to guess what size to make the die.

JoeLee
12-17-2010, 12:54 PM
JoeLee, how about making 2 tapered wedges that look like adjustable parallels that are narrower than the tubing. Then you can press on one of them to push the sides out, and depending on how much you press, the size is adjustable. This way you don't have to guess what size to make the die.

Thats a good idea, however you'll only be pressing on two sides which may result in concaving the other two.

JL.................

Oldbrock
12-17-2010, 01:59 PM
Your idea of making a mandrel a few thou bigger than the inside tube is ok. Just force it in with a press using some antisieze compound then using a hammer lightly tap it all over until the mandrel moves freely. Use planishing type blows all over and it will form to the propper square. It's a good job they are short otherwise it would be a major pain. Peter

MCS
12-17-2010, 03:54 PM
Make a block that slides in the tube.

Push it tight in the troubled section and start hammering the weld on that side. There it is shrunk(?), hammering will lengthen it.

Don't start with a sledge hammer and support the workpiece.

Black_Moons
12-17-2010, 03:58 PM
Grind down the tube thats supposed to fit into the deformed tube.. :)

oldtiffie
12-17-2010, 05:05 PM
Back in Sept. I posted some info on some 2 1/4" sq. telescopic tube I bought from a supply house that was not square. Anyway, they sent me a piece that was acceptable and I returned to the project. The 2 1/4" sq. tube fits perfectly over the 2" sq tube with just enought clearance as it should. How ever, after welding the gussets to the side of the 2 1/4" tube the 2" no longer fits inside. I had a feeling that welding to the 2 1/4" would play out this way as it always does. Looking at the pictures you can see where I started to file the inside of the tube where it's binding. I know I can get it to fit again by filing but thats really time consuming. So.......... the $50 question here is can I swage the tube out to open it up enough to fit again. My thought is to make a 2" square die, tolerance it a few thou over the measured size of the 2" tube that I have to go into it, radius the edges, polish it up a bit and with some oil press it through the 2 1/4" piece with hopes that it will expand it just enough to make it fit again. I know the die should be hardened to eliminate the chance of galling as it's pressed through but I'm just wondering aprox. how much over size I should make the die as compared to the OD of the 2" tube. I'de hate to fall short by a couple thou and have to make another die, and I still have to weld down the sides of the gusset wich will only add to the problem. Any one have any idea on what to expect here??

JL.........................

http://i911.photobucket.com/albums/ac317/JoeLee09/Empty1/Image008.jpg
http://i911.photobucket.com/albums/ac317/JoeLee09/Empty1/Image007.jpg
http://i911.photobucket.com/albums/ac317/JoeLee09/Empty1/Image006.jpg
http://i911.photobucket.com/albums/ac317/JoeLee09/Empty1/Image005.jpg

Joe.

I'd suggest that you really do need to go over your welding procedures and sequencing.

There is or seems to be a lot more welding than seems to be required from a structural aspect.

"Fit-up" as well as sequencing, tack welding and small "hit and miss" and "stitch" welding and clamping and fixtues can help a lot.

The more you can reduce or control the "pull" (ie distortion) from cooling welds the better. If you cannot eliminate it then plan for it.

If you are MIG welding try a few 3mm (1/8") tacks and "stitches".

Fill in between the tacks/stiches if you must but it that extra work and welding is not needed why do it?

johnnyd
12-17-2010, 05:06 PM
Might be a good job for a die filer. :)

PeteM
12-17-2010, 06:19 PM
Or just a file.

The Artful Bodger
12-17-2010, 06:46 PM
To answer the question in the opening post...

I suggest making a die that is about the same size as what you want to slide through.

Drill a hole in the die and tap it with a tapered tap (yeah, kludge I know) then put cross cuts in the die so that you can expand the die by screwing in a bolt.

With that you will be able to stretch the steel in stages and sneak up on the perfect fit!

IMHO of course!

lane
12-17-2010, 06:46 PM
Had a job about 2 weeks ago very similar to that. Same thing happened. started sanding and filing out a few of the parts . Way to time consuming.Found out i could tap around on the part with a copper block and all would be well with the would. Kind of a stress re-leave Try tapping around with a piece of alum bar are a copper are brass block.

oldtiffie
12-17-2010, 07:01 PM
I've previously posted this "angle plate" that I made for new castors on my shop engine hoist.

I was a very fussy about my set-up, tacking, stitching and "fill-in" welds.

It came out very well when checked against a good square - flat and true.

All it would have needed for good work on the mills or grinders was a fairly mild "lick" on either the mill or grinder.

http://i200.photobucket.com/albums/aa294/oldtiffie/Hydraulics/Hyd-lift1.jpg

http://i200.photobucket.com/albums/aa294/oldtiffie/Hydraulics/Hyd-lift2.jpg

JoeLee
12-17-2010, 09:02 PM
Joe.

I'd suggest that you really do need to go over your welding procedures and sequencing.

There is or seems to be a lot more welding than seems to be required from a structural aspect.

"Fit-up" as well as sequencing, tack welding and small "hit and miss" and "stitch" welding and clamping and fixtues can help a lot.

The more you can reduce or control the "pull" (ie distortion) from cooling welds the better. If you cannot eliminate it then plan for it.

If you are MIG welding try a few 3mm (1/8") tacks and "stitches".

Fill in between the tacks/stiches if you must but it that extra work and welding is not needed why do it?

In some cases there isn't much you can do about deformation. Since I only need four of these there is no point in trying to perfect the procedure. All four of these brackes togather on the frame have to be able to support at least 2000 Lbs. so skimpy low penatration stitch welds on thin wall tube may tear out. So there is no overkill in this welding project.
It's not so much the heat that is causing the internal wall to swell but the cooling of the weld as it shrinks and the gusset is pulled tight to the tube. In the past on some jobs I've I've clamped things so tightly togather, perfectly square and after welding they still remained perfectly square and after releasing the clamps the part pulls. Sometimes you can compensate for movment after a few trial runs and sometimes there isn't much you can do at all. I've had the same experiance with stitch welding, not letting things get to hot and you still get movment.
But anyway, the job is done and I guess I'll make a sq. mandrel and press it through and see what happens. Originally I just wanted an idea of how much larger I should dimension the mandrel over the size of the sq. tube to be inserted........... and no.... grinding down 24' of tube isn't an option.
I guess if I undersize it I can always start placing steel shims on the sides as I swadge it untill I get the right fit. A tapered threaded hole and a split die would tend to push on one end unless you had a tapered bolt, but thats still too much work.

TNX...... for the input.

JL.....................

m.rehme
12-18-2010, 04:11 AM
Joe, I have had the same problem with the 2.25 sliding over the 2" in the past depending on what mill it was rolled in and location of the seam weld and without the welding on it becoming a factor.
I have done a lot of swaging before on thick wall rounds and spring back was a issue, I wouldn't think your thin wall tube would be much of a problem, so I wouldn't think your mandrel would have to be much oversized to give you what you want.

I'd go with way you are thinking and lube it up with some STP mixed with oil and go for it.

JoeLee
12-18-2010, 08:47 AM
M.REHME, Your right about mill tolerances, they can differ quite a bit. However the 2.25 telescopic is hard to find, only found two places in the country that had it. 2.25 is designated telescopic as the weld seam is in the corner in stead of in the center or close to the center as most sq. tube seams are, and there is very little flash. The wall is also about .109 which is also non standard. But back to the subject of mill tolerances.......... When I received the 2.25 the first thing I found when trying to slip it over some 2" sq. I had in the shop was it would only fit two ways, the other two ways it would bind. The 2" was slightly over tolerance, about 2.013 on one side and 2.007 on the other side, not really sq. but OK for sq. tube depending on you application...... that stuff was made in Canada...... I guess they have relaxed tolerances. So I took a piece to a local dist. and explained to the I need to make sure this piece will slip over the 2" all four ways before I buy the 24' length. So we went out into the warehouse and did the slip fit test and found that all the 2" they had in stock was OK. So I bought the length. After welding I now have this problem. The stuff I just bought measures about 2.006 x 2.003, not bad. I did find a short piece in the shop that does fit all the way around, that piece of 2" measure 2.002 x 2.003, don't know where it came from but that gives you an ideal on how tolerances can vary. I'm not off by much here, so swaging shouldn't be a problem. Running around to different suppliers looking for a length that is 2.00 on the money is out of the question, so making a mandrel is the next best idea. I'm just wondering how much oversize it should be to compensate for spring back.

JL....................

Vern2
12-18-2010, 09:57 AM
Sounds like if you keep the 2 1/4 tube from shrinking after welding you wouldn't have to do anything. Put a block inside the 2 1/4 before you weld. Let it cool before you press it out. The 2 1/4 keeps it ID and your good to go.

Working with aluminum slip joint on 1" square tube 1/8" side wall. Then slide in 3/4" x 3/4" x 12" solid bar. I just took it to the mill with a pair of vise with parallels, I shaved it down about .007 on two sides. Worked good. Depending on how much you have to take off the 2" x 2" tube, just face it with your mill. Might be able to use a fly cutter. Mill it slide it, mill it slide it again, don't know how long your piece is. You did say you had four.
Vern

Norm W
12-18-2010, 03:43 PM
As we are not talking optical parts here, why not a belt sander with a coarse belt? Would it take all that long to remove the .003-.004" on even a 5' piece of tube? Maybe I'm missing something but the KISS principle comes to mind.

metalmagpie
12-18-2010, 04:19 PM
Get out your oxy/fuel heating setup. Heat it up. Push your inner tube through it along with a .020" shim. Let it cool. Done.

JoeLee
03-21-2011, 04:19 PM
Here is the update on swaging out the 2 1/4" sq. tube projuect that I was working on. It just takes me a while to get back on some projects.
The first picture shows the die I made. I toleranced it to just slip through the unwelded tube which isn't deformed by heat, I champhered the edges for clearance and went a bit heavier on the seam corner. I greased up the inside of the tube and the die and started to press it through. As the die reached the center where the ear is welded it began to push hard. At that point I was pretty much committed and followed through. The end result was what I wanted........... it did open up the tube enough to let the 2" slide freely through no matter which way I rotated the 2" tube. But what happened was it galled up two sides of the die as well as the inside of the 2 1/4" tube. I had a feeling that was going to happen as when two materials of equal hardness are used. If the die was hardened it probably wouldn't have galled. So now I'm wondering what to do as far as the die goes. I don't have any tool steel of that size so I was wondering what would happen if I made the die out of brass. Being the softer metal I doubt it would gall the steel tube, but I'm wondering if it would expand the tube as the steel die did.

JL.........................

http://i911.photobucket.com/albums/ac317/JoeLee09/Empty/Image010.jpg
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JoeLee
03-21-2011, 04:23 PM
Here is what the outside of the tube looks like from the galling. I didn't see it happening as it was the back side. If I had seen the start of this I would have pushed teh die back out but by then I would guess the damage was already done. It took 5 tons to press that die through. I imaging most of that force was due to the galling.

JL.....................

http://i911.photobucket.com/albums/ac317/JoeLee09/Empty/Image024.jpg

lbhsbz
03-21-2011, 06:49 PM
What about heating the tube that supposed to go inside so that it shrinks and fits inside.

JoeLee
03-21-2011, 07:33 PM
The tube that fits inside is part of an adjustable frame and is 4' long.
There are 4 parts like I'm trying to swage and 4 cross members.
Not feasable to heat those lengths and no telling what would happen if I did.

JL...................

GerryR
03-21-2011, 08:37 PM
Try case-hardening the die using Kasenit. I think a brass die will deform before moving the steel.

doctor demo
03-21-2011, 08:48 PM
Try case-hardening the die using Kasenit. I think a brass die will deform before moving the steel.
Or You could make the block a little smaller then build it back up with hard facing welding rod.

Steve

darryl
03-21-2011, 08:52 PM
This reminds me of a similar problem I had. I couldn't find two pieces of square tubing that would nest together properly- it would either be too tight or too sloppy. My solution to that was to use the sloppy fit pieces, but add a pair of shims to take up the play. The shims were formed around the inner piece, and came short of being full circle (ok, square) by little more than the width of the weld seam. In fact I positioned the bends purposely so the shims would not touch the weld seam.

One shim gets fastened to the inside of the outer tube, and the other to the outside of the inner tube. Besides neatly avoiding the weld seam problem, this method also neatly avoids having the inner tubing falling out when fully extended. It comes out to the extent that the two shims butt up, and that's that. Depending on how long you make the shims, you can choose how much of the inner leg remains within the outer tube.

I made the shims from uhmw, sawing them out on the table saw. This way I got to make them the exact thickness I wanted for a tight but slidable fit of the parts- in other words, little play and only light to moderate force required to slide the legs into the holder tubes. Using some heat I molded these strips around the tubing. Now an interesting part- before putting them in place, I drilled a hole in each side of the tubing. Holding the shims tightly in place, I then heated the uhmw where each hole was, and pressed the plastic into the hole. Did this for both inner and outer tubing. When assembled, there's no way the shims can come out. No nuts and bolts, no rivets, etc. Worked- a treat, as John would say.

JoeLee
03-21-2011, 09:09 PM
Thanks for the input guys, they are all good suggestions that help me build on a working idea. I did think of case hardening the die before my first attempt as I figured this was going to happen but I've never case hardened anything before and I'm not sure the hardness would penatrate to a depth that would do any good. A few thou in depth of hardness wouldn't do as the result may end up worse than my first attempt. Besides to case harden 1018 with that powder don't you have to bake the part for so many hours at a given temp.???
I did think of hard face welding the edges of contact and may still take that approach. I've tossed around the idea of wedges and such but too much machine time and precision involved. Since the part only needs to be spread on one side what I've been thinking of doing is to make a 1/2" thick plate for two sides and cut the die down to squeeze between the plates and more or less stretch the tube. Then if there is any galling it will take place between the die and the plates.
I will post pics on my progress. Sometimes it just takes me a little time to get back on a project......... I have too many of them.

TNX...............JL

spkrman15
03-21-2011, 09:54 PM
Joe,

Weirdscience (darin) has a post somewhere here about a die he built but with a piece of HSS to cut the flash out of square tubes. He was using it to help mate tubing together for hitches. Of course this is all by memory.

I can't find it, but you could PM him.

Rob :)

wierdscience
03-21-2011, 10:04 PM
Here you go,might be of some help.You could possibly build one where the cutter is in one corner and simply rotate it and work form opposite sides to shave out what you need.These were built to remove the weld flash inside of 2-1/2 x 1/4 and 3 x 1/4 tube.

http://img.photobucket.com/albums/0903/wierdscience/DSCF0002-3.jpg

http://img.photobucket.com/albums/0903/wierdscience/DSCF0003-1.jpg

Lew Hartswick
03-21-2011, 10:17 PM
Did you use any EP lub on that "push"??
...lew...

JoeLee
03-22-2011, 12:14 AM
Did you use any EP lub on that "push"??
...lew...

Yes I did use lube.

JL..............

metalmagpie
03-22-2011, 02:40 AM
Hmm. Lots of interesting ideas .. none of them anything a welder would do. A welder would find where something flat got pulled concave, and would heat spots to red heat on the concave side and then hit with water blast to quench, then move along. This will cause local shrinking, which would straighten out the concavity if done correctly.

Would require nearly suicidal nerve, though, for someone not skilled with a torch! :-)

metalmagpie

rock_breaker
03-22-2011, 04:20 AM
Just another thought, use 2 dies one just larger than the outer tube then the second slightly larger than the first. My other thought is a heavy grease and beveled leading edges on the due.

Good luck

Rock_Breaker

JoeLee
03-30-2011, 04:22 PM
Here is the latest update on swaging out the square tube.
Since my steel die galled the hell out of the inside of the tube and didn't do the die much good either, I came up with this idea. I ground two steel plates for preassure plates and made the ram or die block out of brass. I didn't have a piece of brass big enough so I bolted two pieces togather and then machined it down to specs. I used a little bit of heavy way oil and pressed it through. The amount of preassure needed to push the brass die through was much less than that of the steel die. Since the brass has some lubricity properties there was much less friction. The only problem that I had was that since the inside of the tube wasn't perfectly square the brass die had a tendency to squeeze out to one side of the tube and it started to bulge the edge. I noticed this right off the start so no damage was done. That problem was easily cured by clamping the tube between two plates. That gave support to the sides. Why didn't I think of all this the first time???

JL.................


http://i911.photobucket.com/albums/ac317/JoeLee09/Empty/Image025.jpg
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Toolguy
03-30-2011, 04:36 PM
Great solution JoeLee!:D I'm going to file that one away for future reference.;)