[ldbtx]

I think it was Steve S (Otto) a couple weeks ago who posted recommending against making welds that run straight across frame rails. I'm getting ready to remove the factory coupler on my 5' X 10' utility trailer and put on a Bulldog coupler. If I weld up the Bulldog the way it's made, the welds will be at right angles to the long axis of the frame rails. So, Steve, would you recommend that I cut the Bulldog coupler plate so that the welds will be at ~45° to the rails, or do you think it'll be OK the way it is? The factory coupler that's on there now is welded at 90°. GVW of the trailer is 3500 pounds.

Thanks,
ldb

[weldin mike 27]

I did a trailer where I welded a plate on, with the welds parallel to the trailer pull and no welds on the ends, ie square to the pull. The hitch was then bolted to the plate.

[Otto Nobedder]

Keep in mind, when I weld on frame rails, the trailer is in the 25+ ton range, and the cargo is often a HazMat.

I would suggest, as a "best practice", avoiding welds that are square to the rails, but if you pay attention to detail and be sure of your penetration and a lack of undercut, a 3500 GVW trailer will be just fine. I've seen thousands of these things do just fine with crackerbox 6013 welds by amateurs because there's just more metal than the average amateur can screw up.

It's all a matter of perspective. If you're pulling two tons, you need to meet a quality standard. If you're pulling twenty tons, you need to meet a design standard.

As long as you're confident in your skills, the design will work.

Steve S

[GreinTime]

I've personally always used fish plates when welding on frame rails, but I've never done anything major (I think 5 ton would have been the biggest) like Steve or my Dad. I've repaired broken frames by cutting out out sections in a parallelogram and then using fish plates on the outside (or inside) to reinforce the replaced section.

And by fish plate, I mean a plate welded on the outside that has long parallel welds longitudinally, and a rounded point on either end to prevent vertical stress risers along the weldment across the back of a c-channel frame.

[Braehill]

I don't have any disagreement with anythiang stated. Think about it, any weld at any angle other than 90* accross the frame will be longer than it will at 90*. Is it worth changing and causing yourself extra work, probably not in your case.

Professionally designed things fail everyday and some of the craziest things imaginable last forever. Problem is with most utility trailers is the fact that the guys who build them were usually hobby welders who do this on the side, working from a drawing on a napkin. Most will be over welded and under designed. Professionally designed trailers are more likely to be under welded to save costs. Most states don't have a way to inspect these trailers for design flaws or even quality standards in general.

Steve's right about perspective, and unless your going to be hauling 3500# everyday it should be fine, unless your changing it due to a failure, then I would re-think design. Your tongue is usually brought to a point anyway, so the weld is being pulled on at an angle and not at 90*.

Len

[ldbtx]

Thanks for the input and advice, guys. I appreciate it. I figure I'll just weld up the new coupler straight across, the way Bulldog makes it. Yeah, Len, I am replacing it due to a failure -- but it's only a failure of the OEM coupler to operate, either hooking up or unhooking without repeated blows from a hammer or other smiting device. I've finally tolerated as much of that inconvenience as I can. On the bright side, it's a commercially designed and built trailer, which probably only means that the design was sketched on a higher quality napkin. Actually, it's a decent trailer with good looking welds and it tows good, so I'm happy with it. Thanks again, y'all.

ldb