Grapple Failure

[R W]

. I wouldn't say the weld itself failed but it tore the metal right at the edge of the weld. .

I would say that you correct.
The square beam wall thickness is way to light to start with. It should have been reinforced with at least 3/8" plate between the tower and the beam, would extend the
reinforcing at least 10" either side of the tower.
Would also have added a V shaped plate from the lower part of the tower to the beam.

 

[CalG]

This may be naive, but I think hydraulic implements should be designed so that the cylinders can go full to the stops without damaging the implement.

They could have easily put a disclaimer on "Warning, Maximum Hydraulic pressure not to exceed 250 psi!" ;-)

 

[CalG]

Yes, I agree. There has been no pushing with the upper jaw. I'm almost 100% sure this damage is due to the force of the cylinder opening the jaw and bottoming out against the "tower" and crossbar before the cylinder stops engage. I'm curious what the company's reaction would be if they saw this thread.

bhh

Looking at the photos, I see exactly the oposite. Damage on Closing pushing the tower back, compressing (shearing) the cross bar in the HAZ (Heat effected zone, a common failure location)

Think about it, you describe the symptom as no longer being able to CLOSE the grapple. This suggests that the mechanism has been sprung OPEN as in closing on the load.

Not that it makes a difference on the failure, but you should know what forces you are dealing with.

(Plus, a cylinder has much less force in retraction than it does in extension due to piston area. This comment without quantification)

 

[CalG]

And, people should refuse to buy these grapples from companies who cheat to save themselves a paltry $10 while weakening your $1000 grapple investment. They will keep cheating so long as customers are naive to the issue. The design is not the issue. It is a stupid manufacturer decision.

I noticed that some of the grapple manufacturers offer grapples in "professional grade" They look much more substantial than the same maker's "lesser models". The carry a price premium to match! (reference the Precision machine products sold by ETA)

I suppose there is some truth to buying the best.

"Quality endures long after the price is forgotten"

 

[CalG]

Ya tell me about it . Easy fix to fix it and never need another . Makes no since to me either .
I will pay shipping for this broke wildkat if ya want to throw it away . And I will fix it and use it and never complain .

Sent from my iPhone 5 using TractorByNet

No! ME! ME! ME! Send it to ME! I'm closest! ;-)

 

[puckgrinder85]

It still shouldn't happen I agree but if the manf. isn't going to do anything it doesn't mean the attachment is useless. As already stated chaining the jaw shut and trying to open it will allow the cylinder to pull the tower back into position. A few strategic pieces of metal (think about how the forces are applied to it) and it will be as strong as it will ever need to be. The problem is putting the corner of the tower on the side of the tubing. If they had boxed the tower to the upper tube this thread probably wouldn't exist, its just not enough metal to support the load.

 

[CalG]

Yep, Right on every count.

An easy fix!

 

[IslandTractor]

I noticed that some of the grapple manufacturers offer grapples in "professional grade" They look much more substantial than the same maker's "lesser models". The carry a price premium to match! (reference the Precision machine products sold by ETA)

I suppose there is some truth to buying the best.

"Quality endures long after the price is forgotten"

The bottom line here is that light duty 48 or 60" grapples work very well with no failure of the upper jaw cylinder tower so long as the manufacturer doesn't cheat by using lesser materials than originally worked out. All these grapples are copies with minor modifications/improvements. Moving from the well established 1/4" tubing to a cheaper lower gauge tube is done for one reason only, to squeeze a few bucks more profit. In so doing they take a well engineered product and turn it into crap that will fail doing ordinary tasks. People love to complain about lousy quality from China but I'd say this shows we are every bit as talented in that department. There is simply no reason at all to use less than 1/4" wall tube unless you reengineer the grapple with lots of base plates to mount towers on and that would cost way more in labor so it isn't done.

Wildkat may not be the only company in a race to the bottom but they surely deserve to be called out for producing a substandard product. There is no reason to up charge for a "professional" level product. Just build them the way they were engineered to be built and pay the extra $10 or so for material. I forget the actual difference in cost for 1/4" over 1/8" tube but it is in that range for the amount in each grapple. They should be keel hauled for such stupidity and frankly unethical business practices. They cheapened the product compared to the standard and hid that fact from the customer. Did they proudly state they were saving material by moving to thin wall tube? I wonder what else they cheapened? If Wildkat wants to be known as the Harbor Freight of grapple manufacturers they have made a good start.

 

[Red Horse]

Wow do i feel guilty- I'm one of the wildkat 48 boosters who has published many "endorsements" on this site. My point- **** of a value. I paid under 700 bucks delivered to Mass. And guess what? I broke mine too! Not wildkat's fault- my fault.

A lot of good comments here by CalG, Puckginder 85, and Island Tractor to name a few. I don't know how you damaged yours, but I suspect the hydraulic cylinder had nothing to do with it.

What I did was foolishly try to "hog out" a good sized boulder by rolling the grapple forward, opening the jaw, then lowering the upper grapple on the lip of the rock and backing up-and I'm talking about 60 HP (4720 cab), loaded R-4's, and about a 500lb weight block that is adorned with about 60' of 3/8 chain. Next thing I knew the grapple in the "closed position was about 10 or 12" from closure.

Remedy? I took the cylinder off and used a heavy chainfall to pull the grapple to the closed position. then I did a half assed repair by welding the back side and adding a couple of gussets to front. I will beef up the back side when I get a chance with some angle across the top,

Attached are pix showing the two breaks, and three shots of my quicky fix. Also a couple of pix "in action". IMO still a good value! Just have to use your head

 

[Red Horse]

View attachment 367818View attachment 367821View attachment 367824View attachment 367825View attachment 367826Wow do i feel guilty- I'm one of the wildkat 48 boosters who has published many "endorsements" on this site. My point- **** of a value. I paid under 700 bucks delivered to Mass. And guess what? I broke mine too! Not wildkat's fault- my fault.

A lot of good comments here by CalG, Puckginder 85, and Island Tractor to name a few. I don't know how you damaged yours, but I suspect the hydraulic cylinder had nothing to do with it.

What I did was foolishly try to "hog out" a good sized boulder by rolling the grapple forward, opening the jaw, then lowering the upper grapple on the lip of the rock and backing up-and I'm talking about 60 HP (4720 cab), loaded R-4's, and about a 500lb weight block that is adorned with about 60' of 3/8 chain. Next thing I knew the grapple in the "closed position was about 10 or 12" from closure.

Remedy? I took the cylinder off and used a heavy chainfall to pull the grapple to the closed position. then I did a half assed repair by welding the back side and adding a couple of gussets to front. I will beef up the back side when I get a chance with some angle across the top,

Attached are pix showing the two breaks, and three shots of my quicky fix. Also a couple of pix "in action". IMO still a good value! Just have to use your head

Forgot the "action shots"- typical of what I do with this "light econo" grapple' And do't forget, every pd. of impliment weight is one less pound of payload. That oak log by the way is probably about 1800 pds.