Square tubing T-joint


Howdy, I am needing to join (weld) a vertical member of square tubing to a
horizontal member that sits on the floor (all tubing being 2.5" x 3/16").
The problem, as you have likely come across, is that the corner of the
square tubing has a radius, leaving a gap on either end of the piece to be
joined.
How would you tackle this problem?
I can think of using a sharpie and an angle grinder to get it pretty close.
Is this about the best method?
Thanks for any suggestions,
Jon
Reply to
Jon Danniken
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We fill the gap with weld bead.
Reply to
Pete C.
Use the resulting vee between the two pieces to your advantage and fill it with weld.
Reply to
Ned Simmons
How strong does it need to be, how clean does it need to look?
I can think of 3 ways at least to join the two without leaving a 'gap'.
Dave
Reply to
Dave__67
One or two passes will fill the gap. No biggie
i
Reply to
Ignoramus22979
Thanks Dave. It doesn't need to be too strong (it's overdesigned as it is), and I'm not too concerned for appearance. Form follows function, and all of that.
Pete, Ned, and Iggy, thanks guys, you all seem to be in agreement. I'm planning on using 1/8" 7018AC for all of the welds, but to fill in the gap, maybe I should use a 3/32" electrode? Any preference for type?
Jon
Reply to
Jon Danniken
I would use 7018 throughout, and 1/8 for creating those beads. You may want to run it a bit colder so that you do not burn through the tubing.
If you do not need extreme strength, you may have easier time with 6013.
i
Reply to
Ignoramus22979
Scribing a cut line on the sides of the vertical end to match the profile of the horizontal member is easily accomplished with a scriber laying flat on the horiz surface, and then conforming to the radiused edges, freehand.
If the scribe was just laid on the horizontal surface and followed around the radiused edges, the radius lines will increase the diameter of the arcs (which isn't desired in this example).
Larger gaps are scribed by using a compass or dividers, maintaining a vertical orientation (in this example) of the two points of the tool.
Maintaining the correct orientation of the points for other applications is similar to having the adjacent surface contacting the surface that needs to be cut, which would be the as if the horiz tube was meeting the vert tube (the way coping is applied in carpentry/woodworking).
Reply to
Wild_Bill
Almost all square structural tubing is ASTM A500 steel and doesn't require a low hydrogen (xx18) rod. Unless the tube is something exotic, or there's some code requirement, I'd use 1/8" 6010 (DC) or 6011 (AC). They're both all-position rods and easier to run than 7018. But if the 7018 is handy...
Reply to
Ned Simmons
Er, ok. The beauty of welding metal vs. gluing wood is that the parts don't have to fit perfectly. Reasonably close is just fine as long as you can clamp the pieces in proper alignment while welding. The weld filler will fill the gaps with no loss of strength, unlike glue in woodworking.
Reply to
Pete C.
1/8" 7018 should fill it nicely, it did on the square tubing on my sawmill and front end loader. I use 7018 for everything to stay in practice, and to use up the oldest of my supply.
The ends of the piece on the floor will rise up if you weld the inside corners.
jsw
Reply to
Jim Wilkins
Hi Ned, I don't know if it is structural, but my local supplier refers to it as "hot formed", if that helps.
My reasoning for choosing the 7018AC was for it's less brittle qualities. It is most likely overkill for the application, but I figure if I can get the hang of it after some burning some rods up in practice, it wouldn't hurt.
Jon
Reply to
Jon Danniken
Thanks again Iggy. I am comfortable using 3/32" 6013 on 1/8" stuff I stick together, and I'm hoping I can get the hang of the 7018AC after some practice.
Jon
Reply to
Jon Danniken
Uh oh, danger Will Robinson! I was planning on doing just that, too.
Maybe I could clamp on a stiff backer piece to keep it straight? The floor piece is 5 foot long, and the two uprights will be roughly in the middle (all of this being 2.5" 3/6" stock).
Hmmm....
Jon
Reply to
Jon Danniken
Since welding had already been suggested several times, I thought I'd give a suggestion that wasn't entirely welding. I wasn't suggesting that just welding was wrong or sloppy (steel is steel, after all).
Many of us could fill the gaps with weld and have a secure, neat looking joint. Some other time someone may want to fit a couple of parts together and have the weld concealed.
Reply to
Wild_Bill
Welding actually needs a certain minimum gap in order to provide proper penetration, so that the weld achieves fusion for the entire depth of the parts being welded. This is not to say that the bigger is the gap, the better. But a certain gap is necessary for proper fusion. If you are welding a flower pot stand, it is less important than if you are making a trailer.
i
Reply to
Ignoramus22979
Many applications require upset of the opposite side to indicate full penetration, complete fusion.
It's when amateurs believe a weld is applied like hot glue stick, that have really bad results.
Reply to
Wild_Bill
Thanks Randy. I've come across recommendations for that rod in other threads, and I'll pick some up from my supplier to play around with.
Jon
Reply to
Jon Danniken
My choice would be 7014, easy to use, and good at filling gaps. Thank You, Randy
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Reply to
Randy
...
You can't prevent the distortion if you make a good penetration weld. The legs will spring together when you remove the clamps or spacers. I had to stretch the ends of my sawmill's ladder frame apart with a jack to make them parallel.
If you need the strength I'd weld gussets onto the sides.
jsw
Reply to
Jim Wilkins

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