the grade 8 bolts where stronger than the steel!

[sparc]

You didn't say but it looks like you've attached a
snowplow to a SSQA plate.

Why bolt to the QA adapter plate? Why not weld?
As has been said the tubing was undersized for the
application, and putting down pressure on there as
you said significantly increased the loading on those
undersized parts.

 

[Baby Grand]

The bolt holes through the most highly loaded (farthest fibers, on either side) of the section and the direction of loading make for a "tear here" stress riser. I'd wager the bolt holes weren't deburred after drilling, either.
The connection design needs to be beefed up and reconfigured, and it sounds like the OP is aware of this.
Personally, I'd prefer to see some angle iron "wings" welded to the box section with bolt holes thru the angle iron "tabs" as anchoring points.
Or weld a section of flat stock to the bottom of the box, between the box section and the thing you're bolting it to. Drill bolt holes in the flat stock and you remove stress risers from the box section itself.

 

[SPYDERLK]

The bolt holes through the most highly loaded (farthest fibers, on either side) of the section and the direction of loading make for a "tear here" stress riser. I'd wager the bolt holes weren't deburred after drilling, either.
The connection design needs to be beefed up and reconfigured, and it sounds like the OP is aware of this.
Personally, I'd prefer to see some angle iron "wings" welded to the box section with bolt holes thru the angle iron "tabs" as anchoring points.
Or weld a section of flat stock to the bottom of the box, between the box section and the thing you're bolting it to. Drill bolt holes in the flat stock and you remove stress risers from the box section itself.

:thumbsup: Thank you for your [correct] assessment and good design points.
larry

 

[Baby Grand]

Thanks for the kind words, Larry!

 

[SPYDERLK]

I particularly liked the mention of deburring the holes. Few realize the importance of eliminating sharp edges. Fewer think to extrapolate to the holes used in fastening. ... both sides. A deburred machine is stronger, lasts longer, and you dont bleed as much.
larry

 

[lloyd430]

Well so many comments..where to start?

No I do not teach my students to build like this- its what I had in the barn.

"What a rusty piece" - well lets see, its cold here, been cold since Oct- when I built it, do you paint in freezing weather?

Undersized steel, well I'll agree, but its what I had, and it did work till we got that last 18" dumped on us, it failed from my actions. I have bent the tubing for a previous project and it took 4 tons to bend it in the press on the 1" side, so it would hold but I did it in with the down pressure.

Yep my TC40 weighs in at just under #7K, every other weekend I drive up the road 1/4 mile to get coal. With the trailer it weighs in @ 7,234 pounds, the trailer weighs 621 pounds empty. The backs are FULL of rim guard.

I got the 3" channel tonight, 1 1/2" Height and #5 per foot- for those who want the specs. I am eliminating all the tubing with the channel. But still no paint till spring, and its going to be IH red, when I paint my old wagon the plow mount will get the loft overs.

 

[akraven]

It was not "what a rusty piece" but instead "What is the rusty piece" I wasn't sure what I was looking at whether it was a QA plate or something else. I was trying to understand how it all went together,,,that's why I asked for better pic's.

 

[lloyd430]

Akraven- sorry its been one of those days- yep the rusty piece is the quick plate (never got to paint it yet:thumbsup: )
I based my creation off this post http://www.tractorbynet.com/forums/...other-qa-plow-build-thread-3.html#post2965919

 

[Industrial Toys]

I always deburr any hole I drill, but I thought I was just being ****!

What's the importance of it structurally?

 

[SPYDERLK]

I always deburr any hole I drill, but I thought I was just being ****!

What's the importance of it structurally?

Anything with a sharp aspect essentially "sits proud" with lots of material on the structure side - then nothing at the point. When the structure moves/flexes all the non sharp parts have material right beside them to share stress. That part of the structure, perhaps right next to a sharp edge, flexes harmlessly; elastically. - - But that sharp edge sits further out [or in] and must stretch or compress more than neighboring smooth material it is part of. And the edge has no neighbor outboard or next door to share the load. Its deformation is much more likely to be plastic. Enuf and it starts to tear. Less, and repeating reversals just work it back and forth enuf times and it cracks and tears anyway. All the smooth material around is now prying on the sharp root of that crack - and that crack is eating its way into the smooth parts. ... And so on.

larry