Thread: drawbar coupling

Yeah, weld 12mm plate to box section that’s possibly only 3.5-4mm thick and possibly create stress lines along welds if done wrong, really gives confidence. Some, just a bit cynical after some of the things I’ve seen when doing wofs in the past.

Who says that the box section here is 4mm 223?? where did you get that figure from because I cant see it anywhere on the original post.

In any case, welding 12 mm to 3 mm with a weld length of say 150 mm is not going to crack, as long as you are :

1) A competent welder, and understand the need for penetration and the avoidance of undercut.
2) You do the prep on the galv box section properly before you weld it

Ive done this heaps of times and never ever had one come back cracked. Remember its only towing 900 kg.

Not having a go at you, just saying

Was merely making an observation based on what I’ve seen as a past WOF issuer. And as you say weld strength is dependent on preparation and welding skills, speaking as someone who has worked on such projects as a certified welder. To get thread back on track I have used and seen many of these couplings on trailers over the years an never seen one give trouble when used within specs.

Originally Posted by Savage1

I think you can buy the pre drilled plates ready to weld on from repco or super cheap.

Or direct from Trojan

Originally Posted by woods223

Was merely making an observation based on what I’ve seen as a past WOF issuer. And as you say weld strength is dependent on preparation and welding skills, speaking as someone who has worked on such projects as a certified welder. To get thread back on track I have used and seen many of these couplings on trailers over the years an never seen one give trouble when used within specs.

Half of that is using a budget mig to do the job so the weld is barely lukewarm, without cleaning the metal and getting rid of the paint galv and crap, doing the job outside and in the overhead position... The other half is probably amateur hour weld as you learn techniques which is fine except when its a reasonably stressed weld that if it lets go is likely to result in some extreme stress at the very least!