Which way is stronger

stealthbob · Aug 6, 2011

I need to weld some square tube, is it stronger to cut on 45's or is it the same to just butt the pieces together square and weld like that?

I think the angle cut looks better but is it stronger?

Thanks

piman · Aug 6, 2011

Hello Bob,

I read in an article on chassis building not to join at 45 degrees, but join at 90 degrees. You need to cap the open end if you want a neater job.

Alec

cumbriasteve · Aug 6, 2011

No doubt there will be technical data that determines the strength properties of each type of joint, I should think though that if welded correctly it would not really matter for normal use.

When I was building heavy duty trailers that I knew were going to be really used and abused I mitred and put a gusset plate on the internal face of the mitre, this can simply be a bit of flat plate or for a nice visual effect more box section of the same size.

stealthbob · Aug 6, 2011

Ok, thanks.

It was more out of curiosity than outright necessity.

I'm building a rotisserie and have over built it for my application anyway, so it shouldn't matter.

Great site you guys have here, you all have really helped this newb. My welds improve every time I turn on my welder.

dannyp · Aug 6, 2011

i would butt them up square.

joing at 45 degrees may be marginaly stronger but is just inviteing other problems that will outweigh any advantage.

i can see it being a pita to get the cuts spot on and hold exactly in place

Hitch · Aug 6, 2011

Id go with the mitre for strength.
Any strength critical items i have made seem to be mitred in most cases.

Delgado · Aug 6, 2011

No idea which way is stonger, but if you mitre the box you'll get less distorsion when you weld it, and it'll look neater.

TechnicAl · Aug 7, 2011

If the weld metal is stronger than than the plate, the mitre will be stronger. Some steel has a grain, like wood, so along the grain could be stronger than across it. So a mitre, with weld stronger than plate, and with the grain running in the right direction could be stronger than a square butt.
However, the difference will be so minimal it will make virtually no diffrence.

A perfect weld with full fusion and no defects is more important.

stealthbob · Aug 7, 2011

Good info...

Like I said it is only for a rotisserie, I have a "No Compromise" approach with the restoration of this car.....I think I can let the rotisserie be just a tool that gets the job done and not get fancy with it.

If it made a big difference in strength I would go with a miter cut and weld but in this case I'm opting for the easier route.

Thanks again.....

aametalmaster · Aug 7, 2011

I have seen both ways also but i would gap it a little for 100% pentration...Bob

subarc boy · Aug 8, 2011

which angle

when i used to make wrought iron gates i always used a mitre cut then put the 2 bits into the 90 degree angle clamps welded them up allow to cool then bobs your uncle no distortion

Which way is stronger

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