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Tube Welding Question

Posted: Fri Feb 17, 2012 8:03 am
by SPR
I’m in the process of redoing the roll bar for my truck and it looks like that I will need to butt two pieces of 1.75 tube (.120 wall) together end to end. In doing so, I would like to insert a short shunt inside them to help strengthen the joint. Any ideas what I can use for the shunt or do I really need to go that route – just butt weld them? I was thinking that I could sand down a short piece of 1.5 tube (.120 wall) just enough to get it to fit. Does that sound goofy?

A finger bender had me singing the bender blues...
Image

Posted: Fri Feb 17, 2012 9:23 am
by White trash
Use about a 6" piece for the sleeve. Leave about a 1/4" gap between them and drill the 1 3/4 for 3 or 4 plug welds each side.

Posted: Fri Feb 17, 2012 9:23 am
by Danny
Steve, I'm surprised you don't have a permanent crook to that digit!

Posted: Fri Feb 17, 2012 1:53 pm
by bobracing
White trash wrote:Use about a 6" piece for the sleeve. Leave about a 1/4" gap between them and drill the 1 3/4 for 3 or 4 plug welds each side.


Yea, what he said.
The 1.5 should fit without sanding it down, just use a cut (saws all, chop saw, bla bla bla) of some sort not a pipe cutter (crushes tube end) at the butt weld.

Posted: Fri Feb 17, 2012 2:18 pm
by SPR
Thanks for the comments. I bet the 1.5 tube that I messed with a Twin Cities Metal had just enough burr on the end to keep it form sliding into a 1.75 (.120 wall) tube. However, the guys behind the desk didn't think it would work.

Posted: Fri Feb 17, 2012 2:38 pm
by OldGreen
We sleeved some 1.5" with 1.25" from twin cities and it just slid right in. . .no sanding or deburring required.

Posted: Fri Feb 17, 2012 4:56 pm
by tobyw
Screaming Toylet wrote:Thanks for the comments. I bet the 1.5 tube that I messed with a Twin Cities Metal had just enough burr on the end to keep it form sliding into a 1.75 (.120 wall) tube. However, the guys behind the desk didn't think it would work.


I'm no math whizz, but...

Posted: Fri Feb 17, 2012 5:16 pm
by SPR
Toby, I don't find your comment very useful, but I'm sure you didn't mean it to be.... thanks for nothing.

Posted: Fri Feb 17, 2012 11:02 pm
by White trash
:lol:

Posted: Sat Feb 18, 2012 5:45 am
by SPR
OldGreen wrote:We sleeved some 1.5" with 1.25" from twin cities and it just slid right in. . .no sanding or deburring required.


What you did works great when the larger tube (1.5") is 0.95 wall. The smaller tube (1.25") slides in real nice regardless how thick it's wall is.

The 1.75"x0.120 tube has a 1.5"ID and the next size smaller tube is 1.5"OD. Therefore 1.5"OD minus 1.5"ID = 0.0 (as in zero chance that it will slide right in).

I'm going to try cutting a 6" long section of 1.5" tube along its length on one side with a cut off wheel and then crush it down to close the gap. That might reduce the OD of the tube just small enough to slide into the larger tube.

Posted: Sat Feb 18, 2012 8:11 am
by White trash
Your seam may be working against you. 1.75 OD minus .240 wall thickness equals 1.51 ID. That makes things close but not impossible. I have lots of pieces of 1 1/2" tube that slides into 1 3/4x.120", you are more than welcome to it if need be.

Posted: Sat Feb 18, 2012 8:12 am
by Roman
Hey Steve all that would be true IF you were using
0.125" wall tube, but 0.120" wall leave JUST enuff slip. An outer tube diameter of 0.095" leaves far to much slop to be effective.

Jim's tie rod wasn't sanded, but the opening was debured after the chop saw. It slid home with just a slight helpful tapping.

As far as your cage slug, it should slide together just fine. But if you can locate the joint/splice at an intersection, it would help to reinforce everything.

Posted: Sat Feb 18, 2012 8:46 am
by OldGreen
Yep. It should work. If it doesn't after the end is cleaned up then either the tube has a flaw or you are doing it wrong. Toby was saying the same thing that Trash did. The math works. It is possible that the seam is getting in the way, what you are trying to do is extremely common and works every time. 1.51 > 1.50.

Posted: Sat Feb 18, 2012 8:59 am
by tobyw
Screaming Toylet wrote:Toby, I don't find your comment very useful, but I'm sure you didn't mean it to be.... thanks for nothing.


Well Steve, my comment was not truly intended to provide any value to your thread, as you so deftly pointed out, but I will explain it for you regardless:

In general terms, tubing is measured by the OD (Outer Diameter). Now there are several types of tubing, all having different structural properties making them good for various applications. What you didn’t mention in your original post what which type of tubing you were in fact using, but let’s just simplify things and narrow it down to DOM (Drawn Over Mandrel) or HREW (Hot Rolled Electro-Welded). As the names imply, these are very different types of tubing. DOM is what is referred to as “seamlessâ€

Posted: Sat Feb 18, 2012 8:13 pm
by SPR
Thanks for the comments... BTW Toby, I agree with everything you wrote :P