Butt or mitered corners for 2x2 box perimeter

[Juneaudave]

On my last trailer, I used mitered corners on the perimeter (2x2x1/8 box). Is there a welding reason or some other resaon to use a butt joint? I see trailers built both ways but can't remember seeing it discussed.

[prohandyman]

Dave
I had a similar question for my welder, and he replied that it really didn't matter, just a cosmetic issue. He welds them butt joint and fills the open tube with a cap. Not cosmetic for me because I hide the frame anyway.
He also said not many people can cut a true enough miter to accurately weld it solid( in his opinion)

[Dean in Eureka, CA]

Well... Questions like that can drive a Norwegian crazy.
I ended up mitered mine, but considered butting them for a long while, leaving the side rails long for a nice concealed wiring chase, with removable end caps.

[doug hodder]

I find that a butt joint makes for a lot easier squaring up of the frame. But then I don't have a table to weld on....just a concrete floor. I've fought mitered corners also, can't quite get it perfect, just not worth the effort for me.

[Juneaudave]

Thanks all...that makes sense. I can understand about cutting miters and getting them square. Seems like I wore out a disc or two fine tuning my highly accurate skill saw miter cuts with my dainty, finishing grinder...

[Ageless]

While I'm not a welder; my tooling work involved building huge jigs that held sections of aircraft. The bases were welded from large square tube. They cut one section square and the end pieces were cut in a fashion that left the outside wall in place to act as an end cap to the mating tube.

[doug hodder]

Dave....might be an idea to get a really cheap beater miter/chop saw from a pawn shop or garage sale and install an abrasive wheel on it. I've done that with an old B&D one....pretty much makes them junk after a while however, I got a lot of work out of it before it died though. I've got a HF chop/miter saw for iron, but did put on a good US made wheel. The Russian made blade that came with it had a serious wobble and bound up and exploded....got interesting really fast! Just an idea. Doug

[madjack]

...yep, mostly personal preference...I miter...I found that using a miter/chop saw sucks...I MUCH prefer using a thin cutting wheel on a side grinder...make the cut barely short of the mark leaving a hairline of gap and then welding the heck outta the joint...for me, this seems to give better penetration with a wire feed welder...if you butt joint, the corner curve gives a good gap for the weld to fill.......
madjack

[Juneaudave]

I did end up buying a chop saw (and a new skill saw) a while back after the arbor on the skill saw started to wobble from all the grit and crap messing with the bushings [smile:="guntohead_u_idiot'] What I really wanted was a good bandsaw but couldn't afford the ticket to the dance...

[laoutdoorsman]

yall need to look into a metabo saw....its a brand name, but in my work, over the years, it has become a generic name for the tool, no matter what brand it is...

its like a right angle grinder on steroids...turns alot higher rpms, starts soft, wont "bog down", takes a large (7 inch, 6 inch, or you can use the 4 inch in tight spots) paper thin cutoff wheel....

metabo is the original, black and decker industrial makes one, dewalt makes one(it sucks though), and milwaukee makes one(it sucks also).....some have a squeeze trigger, get that kind...some have a switch on top(sucks!!)
it has an arbor(5/8 screw) just like a grinder, so you can use grinding blades on them also..(i dont think its recommended, though, but i do it ALL the time)

they are the bomb fro cutting steel...i use it for everything(i actually use to grind also, instead of swapping tools), ive got 4 or 5 of them laying around over here, and they are worth their weight in gold---i rarely even use my portaband anymore...

it cuts as straight as you can manage and leaves an nice neat edge...it will cut thin stuff in a heartbeat...thicker stuff, it cuts awesome, just takes more blades...

at work, ive cut 10, 12 inch schedule 80 pipe (1/2, 5/8 thick wall) with it no problem....it took a little while, and alot of blades, but the edge looked like it was cut with a machine...(as long as you follow the line!! lol)...of course, i have cut way more than that, just an example...its our tool of choice on the job...the safety people hate them,(banned in some plants) but most of us carry our own personal one in our toolboxes...they are just too great of a tool...

[Shadow Catcher]

My reply would be it depends on your fit up skills and welding ability. In the process of learning weld inspection I did a bunch of welding, learning how to put mistakes in (I would not want to do my own welding). I have seen enough failures some catastrophic that I will take what ever it is to a currently certified welder with the right certs. I used to do the Xray, ultrisound, and mechanical examinations of the test welds. some were scary

[dh]

yall need to look into a metabo saw....its a brand name, but in my work, over the years, it has become a generic name for the tool, no matter what brand it is...

2ng the Metabo

Used them all the time while I was chasing heavy construction work. A little pricy though, so I just use a cut off wheel on an angle grinder.

[jamscal]

While I'm not a welder; my tooling work involved building huge jigs that held sections of aircraft. The bases were welded from large square tube. They cut one section square and the end pieces were cut in a fashion that left the outside wall in place to act as an end cap to the mating tube.

That's called coping, and is the 'strongest' of the three joints mentioned.

I butted mine.

Don't worry about a super accurate fit-up. Most welds could use a gap or opening anyway, within reason.

Metabo is a German maker of grinders and other high-quality tools. I have one of their angle grinders and will never buy another brand.

[mwallace61]

Mike,

What model #'s do you recommend?

Mike

yall need to look into a metabo saw....its a brand name, but in my work, over the years, it has become a generic name for the tool, no matter what brand it is...

[Larwyn]

I usually use the Triton Steel Cutter for miters in material 2" and under with good results. It is much like a chop saw but uses a carbide tooth blade, is set up for 90 or 45 degree cuts and has more safety features than you can imagine. It is shown in this picture of my "Triton tool collection", it is the one that says "Triton Steel Cutter" on the side.
Though this saw makes rather accurate 45 degree cuts, I agree that extreme accuracy in the cut is unnecessary as allowing a little gap between the two pieces in a weld promotes better penetration and a stronger weld. Proper setup and welding procedure can result in square frame with less than perfect cuts.



I used that Triton saw to make all the miter cuts on close to a dozen of these panels. Due to the notch required on each end of the bottom, each panel had 8 mitered corners (that's sixteen 45 degree cuts per panel). I guess I never got around to taking a picture of this project after the panels were painted and properly installed. They are just propped into place in the pic, after I actually installed them they are all plumb and square with each other. It was a fun project I did for my wife's mom. She had originally requested that I fill those spaces with wooden lattice panels, she decided she liked my design better...