Silly newb question

[Dangle_kt]

I am going to be making a small (6x4) fully enclosed box trailer, I have all the suspension, sorted and the plan I was thinking of was something like the picture below for the exterior frame base, 3x3 mild steel box (there will be other cross members etc)

my question is, are 45 degree to 45 degree corners needed or is it just as strong to weld edge to end?

The reason i ask is my chop saw never seems to cut accuratly, I can check and check it, but it seems to cut on the cock, so 45 degree to 45 degree corners always end up with a massive root at one end and nothing at the other.

cheers

 

[Baz-Cem]

When I'm making box frames I just tack it together and check the square with a set square and measure corner to corner. My chop saw is kack also so I always have square it up and finish welding.

I 45 my joints as I think it looks far better and there maybe an argument the the joint is stronger.

Baz.

 

[Archie]

I would have though 45 degs would be better for a trailer as it'll stop water, salt etc going down the tubes and sitting in there. I suppose you could plastic cap the ends but an angled cut looks neater. I find the only way to get a half accurate angle measure off the chop saw is to ignore the rubbish markings and measure the angle off the blade.

 

[Dangle_kt]

glad its not just my chop saw then! I knew I should have bought a band saw! DOH!

Thanks for the replies - I had thought about the open ends, I was going to weld it up with some plate.

Guess I'll have to ignore the chop saw and measure it properly.

Are there metal pertractors? (spelling) and what do you guys use to mark steel, pen doesn;t seem to be very visable.

 

[Archie]

For accurate marking a scribe, for less accuracy engineers chalk.

 

[Baz-Cem]

Paint pens aren't bad, espesaily on oily box section.

 

[runnach]

If you are ever knocking up a square or rectangle frame, best to make up into L's, fully weld each one, then knock it about till square. Then offer up 2 L's to each other, tack, then fully weld till complete, once cool, check diagonals. If each measure the same, voila, if not, dunk the highest corner till both measure the same.

Easiest and most accurate way to make a frame.

Oops, forgot to add, mitre corners are far better and neater too.

 

[Dangle_kt]

If you are ever knocking up a square or rectangle frame, best to make up into L's, fully weld each one, then knock it about till square. Then offer up 2 L's to each other, tack, then fully weld till complete, once cool, check diagonals. If each measure the same, voila, if not, dunk the highest corner till both measure the same.

Easiest and most accurate way to make a frame.

Oops, forgot to add, mitre corners are far better and neater too.

dunk the corner? what does that mean?

 

[Baz-Cem]

I assume he means drop it on the corner with the longest measurement until they both are the same.

 

[runnach]

Depending on size and matl t, bash the corner required to bring to square using gravity and concrete floor.

Should have explained better........sorry, had a few beers and dunk at the mo hehehe........

 

[runnach]

Cheers Baz, spot on, you got in before me!!