Grappling fun - A Picture Thread....

[fruitcakesa]

Well, my grappling has ground to a halt; I was digging out a boulder with the forks and trying to grapple onto it when this happened:
I know that the whole rig is made of mild steel, none of the fancy$$$ AR stuff. Thus the low price tag.
I wasn't really working it any harder than usual but it possibly was a cumulative weakening and failure over time due due the lower grade materials.
I will take it over to my welder friend and get his advice on possible repair.

 

[dragoneggs]

Ouch! Hope it is fixable to a workable state. That looks pretty bad. I'm surprised you had a catastrophic failure before something just got bent.

 

[Jstpssng]

Well, my grappling has ground to a halt; I was digging out a boulder with the forks and trying to grapple onto it when this happened:
I know that the whole rig is made of mild steel, none of the fancy$$$ AR stuff. Thus the low price tag.
I wasn't really working it any harder than usual but it possibly was a cumulative weakening and failure over time due due the lower grade materials.
I will take it over to my welder friend and get his advice on possible repair.

That doesn't look too bad though. It seems like you may want to have the pivot point done differently also.

There's a saying around here; if it's iron it's going to break.

Looking at it again it shouldn't be too bad at all... to do it right they would cut the broken piece out and replace it. If I was doing it I would weld a heavy pieve of angle over the break put a bushing in where it attaches to the cylinder, and weld it back together.

 

[fruitcakesa]

Ouch! Hope it is fixable to a workable state. That looks pretty bad. I'm surprised you had a catastrophic failure before something just got bent.

Yes, it was kind of a slow motion failure. I had just finished lifting/pushing the boulder out of its hole when the Thumb just closed by itself.
I hit the control lever to reopen it and nothing happened. Took a look and found the damage.

 

[Gordon Gould]

Well, my grappling has ground to a halt; I was digging out a boulder with the forks and trying to grapple onto it when this happened:
I know that the whole rig is made of mild steel, none of the fancy$$$ AR stuff. Thus the low price tag.
I wasn't really working it any harder than usual but it possibly was a cumulative weakening and failure over time due due the lower grade materials.
I will take it over to my welder friend and get his advice on possible repair.

Ouch is right. But your welder friend should be able to fix you up. Mild steel should be fine there with a good joint design. AR is for Abrasion Resistance for the most part. The problem I see is all the force is concentrated on those two smallish welds. I would think that it would be best to make that joint so the force is spread over a bigger area by adding some gusseting as jstpssg alluded to.

gg

 

[IslandTractor]

Well, my grappling has ground to a halt; I was digging out a boulder with the forks and trying to grapple onto it when this happened:
I know that the whole rig is made of mild steel, none of the fancy$$$ AR stuff. Thus the low price tag.
I wasn't really working it any harder than usual but it possibly was a cumulative weakening and failure over time due due the lower grade materials.
I will take it over to my welder friend and get his advice on possible repair.

It looks like it broke because the thumb was used to push something rather than just close. Is that what happened? Mild steel should be fine for a grapple arm and I have a hard time imagining that the hydraulic cylinder could generate enough force to rip the welds apart. Pushing with the grapple arm open however might do that if you have a heavy tractor, momentum or a heavy load.

 

[fruitcakesa]

It looks like it broke because the thumb was used to push something rather than just close. Is that what happened? Mild steel should be fine for a grapple arm and I have a hard time imagining that the hydraulic cylinder could generate enough force to rip the welds apart. Pushing with the grapple arm open however might do that if you have a heavy tractor, momentum or a heavy load.

While I never intentionally used the grapple to push with, I suppose it is possible.

 

[IslandTractor]

While I never intentionally used the grapple to push with, I suppose it is possible.

Well, if that is the case then the silver lining is that the grapple should be fine after some welding. It looks to have been constructed with 1/4 inch square tube which is what good grapples are made of (the 1/8" tube saves a few bucks but damage like this is far more common). I'd weld it back together and then just be careful about ever pushing with the grapple arm open and in contact with anything.

 

[fruitcakesa]

Well, if that is the case then the silver lining is that the grapple should be fine after some welding. It looks to have been constructed with 1/4 inch square tube which is what good grapples are made of (the 1/8" tube saves a few bucks but damage like this is far more common). I'd weld it back together and then just be careful about ever pushing with the grapple arm open and in contact with anything.

It is 1/4" and it's fixed, likely better than new. Steve, the welder, showed me the voids in the original welds. He grou

 

[dragoneggs]

Great to hear and see! Seems it wasn't so twisted as I thought so the fix wasn't so hard?

 

[IslandTractor]

It is 1/4" and it's fixed, likely better than new. Steve, the welder, showed me the voids in the original welds. He grou

Glad to hear that it’s been fixed. Should be good for at least 25 years of grappling!

Not sure I’d blame the original welds though even if there was some porosity. It looked like base metal was just ripped as the edges were quite ragged. We all make mistakes and I’d say accidental “operator error” was more likely the root cause. Don’t worry, we’ve all done stuff like that. Just be glad it could be fixed with a simple weld repair.

 

[fruitcakesa]

Glad to hear that it’s been fixed. Should be good for at least 25 years of grappling!

Not sure I’d blame the original welds though even if there was some porosity. It looked like base metal was just ripped as the edges were quite ragged. We all make mistakes and I’d say accidental “operator error” was more likely the root cause. Don’t worry, we’ve all done stuff like that. Just be glad it could be fixed with a simple weld repair.

yes

 

[Gordon Gould]

Glad you got fixed up and can go again. Maybe that fix will last for a long time but this is my thinking on what happened - Those original welds held fine it was the 1/4 tube that got ripped apart. Every time you close on something the force from the cylinder ram pushes on the tops of those lugs which puts a forward twisting force on the cross member. Pushing the lugs forward against a stop will rip them out at the base. The same happens when you put an upward force on the top jaw by bashing around. The upward force on the jaws tries to rip the lugs out of the tube. That is what I think happened. The 1/4 tube was stronger at the welds because it was effectively thicker (stronger) due to the weld material so the ripping force concentrated around the edge of the welds and that is where the tube failed. If it were mine I would make those lugs larger and triangular so they could be welded onto the cross tube and also welded to that center tube 90* to it. Giving a bigger area to spread the stress. But that's just me.

gg

 

[IslandTractor]

Glad you got fixed up and can go again. Maybe that fix will last for a long time but this is my thinking on what happened - Those original welds held fine it was the 1/4 tube that got ripped apart. Every time you close on something the force from the cylinder ram pushes on the tops of those lugs which puts a forward twisting force on the cross member. Pushing the lugs forward against a stop will rip them out at the base. The same happens when you put an upward force on the top jaw by bashing around. The upward force on the jaws tries to rip the lugs out of the tube. That is what I think happened. The 1/4 tube was stronger at the welds because it was effectively thicker (stronger) due to the weld material so the ripping force concentrated around the edge of the welds and that is where the tube failed. If it were mine I would make those lugs larger and triangular so they could be welded onto the cross tube and also welded to that center tube 90* to it. Giving a bigger area to spread the stress. But that's just me.

gg

Good point but the real issue is simply that grapple arms are simply not engineered to have anything pushing against them when open. The closing force is easily calculated because you can figure the geometry and hydraulic cylinder force but if the jaw is open and a tractor is moving or pressing against a large immobile object, then you can quickly exceed the design parameters. Lots of grapples get injured pushing against a tree with the upper arm in contact when open. Analogous to using your own hand. You can grip something as tightly as possible and you don't hurt your fingers, but if you have your hand open and bend the fingers backwards you injure yourself pretty easily especially if you are moving.

 

[Jstpssng]

I'll stand behind my original statement about that grapple repair; if it's iron it's going to break. That's why we have welders.

Glad that he got it fixed, although I still would put a bushing in that gap where the cylinder pin connects.

 

[fruitcakesa]

I have been using it again and of course it works fine, but this operator will be paying more attention to operation.

 

[sdarnold09]

Took a while to move these. First job with the new workmaster!

 

[Jstpssng]

^^^^^

Nice looking setup. :thumbsup:

 

[goeduck]

I will push brush with my closed grapple lid to get more surface area against the brush, but I never push anything solid with the lid. For that I open the grapple and push with the bottom tips. Just remember a tractor FEL is not a dozer so be careful not to damage things.

 

[davedj1]

I guess I can add to this thread now
Picked this up off of marketplace the other day.
I already had the hydraulic kit sitting in the garage for the Kubota

I had to convert it to quick attach

I would like nothing more than to have some action shots but I don't have anything here to work with If we get a cooler weekend I will run up to camp and try it out