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.

 

[IXLR8]

Wildcat's poor construction on this model is a turn off for me, but that would not stop me from considering one of their grapples. BUT, no or poor response to the OP would convince me to eliminate them as an option. A major factor for me for considering a product is how a vendor reacts AFTER the sale. We shall see how, if, Wildcat responds.

 

[puckgrinder85]

The more I look at the pictures the more I see wrong. The tower itself is bent. That's some pretty substantial metal to bend, especially that direction. Something isn't quite what it seems to me. Either the ram is way too big for what its being used for or it has way too much leverage on that tower and literally bent what looks to me like 3/8? steel at least.

 

[7879fordman]

The more I look at the pictures the more I see wrong. The tower itself is bent. That's some pretty substantial metal to bend, especially that direction. Something isn't quite what it seems to me.

<img src="http://www.tractorbynet.com/forums/attachment.php?attachmentid=367830"/><img src="http://www.tractorbynet.com/forums/attachment.php?attachmentid=367831"/><img src="http://www.tractorbynet.com/forums/attachment.php?attachmentid=367832"/><img src="http://www.tractorbynet.com/forums/attachment.php?attachmentid=367833"/>

Ya that looks like some hard abuse to me .or improper use .

Sent from my iPhone 5 using TractorByNet

 

[Oliver1655]

While chaining the jaws together then trying to raise the jaw to pull the tower back in place sounds like a good idea, remember you will not have the same tonnage in that direction due to the surface area lost by the space the ram occupies so it might not work. If it was mine to repair:
- Disconnect the cylinder
- Cut the cylinder mount/tower off.
- Cut out the deformed portion of the tubing & weld in another piece.
- Use 2 - 2' lengths of 3/8" angle iron to cradle/sandwich where the cylinder mount was cut off. You will have to notch where the flats are between the upper & lower horizontal tubes.
- Weld the cylinder mount back in place.
- Use 3/8" angle iron to go from the lower tube up to the cylinder mount on both sides with one edge of each facing the tractor.
- Weld a piece of 1/4" wall square tubing between the upper & lower horizontal tube in front of the angle iron you added & tie/weld it all together.
- Consider strengthening the tubing at the pivot points as well.

Point to remember:
- Assume the spacing for the mounts were appropriate for the cylinder when you first got it. ie: The grapple closed completely with the cylinder fully extended & the grapple would open fully with the cylinder fully retracted without the grapple hitting a stop.
- When you have a load in the jaws you have to use your judgement as to how much pressure to use while clamping the load. Odds are the cylinder is too large a diameter for the build. I have a 2.5" cylinder on my grapple & I have to make sure I don't over do the pressure. A lot of the grapples I see only have a 2" cylinder for this reason.
- To allow you a safety margin, consider exchanging the current cylinder with a smaller diameter one. (This will also make it move faster. - A plus!) Yes I understand it should have been designed to withstand the force of the cylinder they supplied with it & the repair will be much stronger than it was to start with. However it is easy to get distracted or if someone else is using it to apply too much force.

Wish you the best. Overall it doesn't look like a bad design, they just failed to have an adequate mount point. Redo it & it should last you a long time.

 

[IslandTractor]

I have had an equivalent size and style 48" 300lb grapple now for about 7 years. I used it first on a CK20 with 1000lbs lift and for the past five years it has been mounted on a DK40 with 2700lbs lift. I've beat the crap out of the grapple clearing trees, boulders, stumps and roots. I have accidentally "pushed" with the upper jaw when trying to push a tree over. No damage to the grapple. I managed to bend the very tips of the upper jaw when clamping on a 2000lb chunk of granite I pulled out of the ground. (easy fix, heat and then gussets to better support the tips). The basic grapple is as true and stable as the day I took delivery. It is constructed of 3/8" mild steel tines and ?3x3x0.25 square tube and some heavy ?2" pipe between the tines for support. It is the same basic style as the Wildkat. Mine is a Millonzi (out of business, principle died) and cost $500. I have never heard of a WRLong OBG style (similar) breaking. I don't recall hearing of the Markham grapples breaking. I'm pretty sure all of those grapples of very similar design and weight are built with 1/4" top tube. The top tube is what is failing on these Wildkats so I have a hard time imagining that it isn't simply inappropriate 1/8" material that is the cause.

 

[murphy1244]

Ya that looks like some hard abuse to me .or improper use .

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more likely the grapple is a POS.

 

[CalG]

I'm paying a buck 65 a pound for hot rolled.

What do you suppose that POS is worth in scrap?

Now, add the fabrication costs and tell us how to do it better.

Add metal ($$$$) And what do they say to the customers who complain that the the grapples are too heavy for thier BX's and the costs are too much for a hobby farm?

Easy fix!

Pissing and moaning won't get anything but more regulations and higher prices!

 

[puckgrinder85]

After seeing that bent metal I just cant believe its had an easy life. I've bent buckets and just about anything else I've owned at some point and really they've all come from me overstressing them. The tractors system pressure relief is set to a max and that cylinder doesn't look way oversized for the grapple either. Its not a woodsplitter its just a thumb to grab stuff with..

 

[IslandTractor]

I'm paying a buck 65 a pound for hot rolled.

What do you soppose that POS is worth in scrap?

Now, add the fabrication costs and tell us how to do it better.

Add metal ($$$$) And what do they say to the customers who compain that the the grapples are too heavy for thier BX's and the costs are too much for a hobby farm?

Easy fix!

Pissing and moaning won't get anything but more regulations and higher prices!

Several companies have made this same style grapple weighing between 300-350lbs and using appropriate gauge steel. These are not designed for BX loaders which only lift 500lbs or so. These would be used on B and L size tractors in the Kubota line and CK or DK or NX in the Kioti line. Not sure of the equivalents for JD, NH etc.

You ask how to build them better? Easy. NOTHING less than 1/4" mild steel anywhere on the grapple. Square tube wall = 0.25" Tines =3/8" Use Sch 80 pipe for reinforcement between tines. Copy the simple Millonzi basic design but improve the upper jaw by making it a tad wider and better protect the cylinder/lines. Not rocket science.

Build it well and folks will pay a grand or more plus shipping without complaint. At $1.65 a pound for steel that means roughly $500 in material. Build it with $10 less steel in it and you'll have a POS. If you want to save $10 on steel by using 1/8" wall tube then cut and weld base supports but I cannot imagine that would be cost effective compared to just using 1/4" wall tube to start with.

 

[94BULLITT]

BHH, sorry to hear about your grapple failure. There is way to much hype on this forum of the economy grapples. This shows what happens when you actually use them. Like you said it is not much of saving once it breaks. I remember a few threads on here of people having the same problem with the Wild Kat grapple and they said the main tube is 1/8'' wall. If the main tube on your grapple is 1/8'' wall it is a design flaw. It shows how much R&D went into this grapple. If Wild Kat was supposed to call you back they did not I would call them again, I would not give up too easy. They need to at least know this is a problem with their product and correct it before they sell anymore. Someone earlier suggested chaining the lid shut and opening the lid to bend things back into place. This may bend things back close to new but since that main tube has already been bent once it won't take much to bend it again. I think the only way to fix it is to put a whole new main tube on it. While you are at it you may want to add a cylinder protector to the lid.

The more I look at the I the more I see wrong. The tower itself is bent. That's some pretty substantial metal to bend, especially that direction. Something isn't quite what it seems to me. Either the ram is way too big for what its being used for or it has way too much leverage on that tower and literally bent what looks to me like 3/8? steel at least.


View attachment 367830View attachment 367831View attachment 367832View attachment 367833

I think it has too much leverage and the main beam is too thin.