Box Blade Build

[Shield Arc]

If you look on the opposite side from the hole, that weld is just setting there. I would knife edge bevel the plates, and weld all the way around.

 

[jb1390]

If you look on the opposite side from the hole, that weld is just setting there. I would knife edge bevel the plates, and weld all the way around.

There is a small chunk gone from the 3/8" plates where that weld is "setting there". While you are correct that joint prep could be "better", I highly doubt that it would have affected the failure. While I didn't see it happen, based on the aftermath it appears to have pulled the chunk out, and then broke the opposite weld at the root.

I don't think joint prep is the only answer, I think it either needs a thicker front plate to supplement the 1/4" wall, or gussets. The thicker front plate would be better for pin access, but more difficult and time consuming. Adding gussets Would be quick, just need to make sure I can still get at the pins.

Shield Arc, FWIW, if I do add a 1/2" plate to the front of the beam, I will definitely do a bevel.

 

[Shield Arc]

Yeah, see that's one of those tough calls. You make one area strong, then what does it tear up in another area? The box tube is a weak zone in this case. My mind set is, if both welds were at there best, would it have broke? Don't know! But I'm sure if the plates were beveled in the first place the welds would have had a better chance of survival on impact.

 

[jb1390]

Yeah, see that's one of those tough calls. You make one area strong, then what does it tear up in another area? The box tube is a weak zone in this case. My mind set is, if both welds were at there best, would it have broke? Don't know! But I'm sure if the plates were beveled in the first place the welds would have had a better chance of survival on impact.

Can't argue with that...it's obvious that that weld should have either had more penetration or overlap with the part at a minimum. Whether it would have saved that tooth there's no way to know for sure.

I was thinking about possibly opening up the front where the tooth attaches, so that if the pin were to shear, the tooth would fall out. So then I'd basically have shear pins for each tooth. Seems like that might be the best of both worlds....build the center beam up further, and then use a designed weak point that is easy to fix.

I am glad, for what it's worth, that the blade is what gave out and not something on the tractor. This type of thing is exactly why I built this blade, since I used to do work like this purely with the loader. I'd much rather rip teeth off all day long than have to fix tweaked loader arms.

 

[Shield Arc]

I'd much rather rip teeth off all day long than have to fix tweaked loader arms.

Yeah no kidding! Like I said it's a tough call, you need a fuseable link some where. Hopefully in a place that easy to fix, and doesn't cost a lot to do.

 

[jb1390]

Yeah no kidding! Like I said it's a tough call, you need a fuseable link some where. Hopefully in a place that easy to fix, and doesn't cost a lot to do.

Yeah I'm thinking when I get around to fixing it, I'll do some calculations to see grade/size of bolt that would be applicable. My gut feel is a 5/8" grade 5 bolt that will shear. I'll probably also mount the tooth with a chain or something on top, so it doesn't disappear into the pile if the pin breaks.