LA724 loader concern

[Heywood Jannockitov]

Yeah, I guess there's still Frey, and of course Horst buckets, pallet forks and spears. I put a new 2000 lb Frey quick attach loader on my IH 454 23 years ago and it has been tough as nails.

 

[dfkrug]

You cannot compare the John Deere and Kubota curved booms one for one. If you look at the John Deere boom it is formed in two halves and then welded down the center. The Kubota is bent in a U shape and then welded on the bottom side. Went and looked at the 724 loader today at dealer and they waves are angular in formation like they were put there by a brake or a stamp so they just may be part of the design as some people said before when you shape something in a curve the extra metal has to go someplace. I may be wrong but it is something to think about.

I was wondering when someone would point that out. My Kioti curved
boom loader is made yet a 3rd way: It uses rectangular tubing that is
bent by the hydro-former or press. I does have some wavyness to it.
The U-shape that Kubota uses is interesting in that it provides the
pocket for protecting the hyd lines. Is seems obvious to me that if you
bend a U-shape that way (vs a box shape), you will get rippling. But a
full box shape should have less rippling.

I wonder...is the underside welding continuous or stitched?

 

[Jibber]

This may be apples and oranges.. because I have an older 723 loader.. But there are no waves in mine. Straight as can be. Also.. my BX has the curved loader arms and they are also straight.. no ripple or buckling that I can see.

 

[DWCox]

This may be apples and oranges.. because I have an older 723 loader.. But there are no waves in mine. Straight as can be. Also.. my BX has the curved loader arms and they are also straight.. no ripple or buckling that I can see.

Thankfully the Kubota tractor is still manufactured and assembled in Japan, with only the FEL and backhoe being manufactured in the new plant in the U.S. If Kubota becomes sufficiently aware that the loader quality may be hurting their brand, they will likely take steps to address it.

 

[weber farms]

My LA724 loader looks as smooth as the Deere loader, however I think the kubota loader is much more substantial and heavier. I think kubota builds loaders to be strong, not pretty. I am quite surprised deere loaders are not made of plastic like everything else on their tractors. (just kidding about the plastic).

 

[Happyman]

My 724 FEL also has the "Waves". I'm not concerned about cosmetics. It could look like a Lego for all I care as long as it holds together and works for me. These are tractors, not BMW's.
I put my FEL through **** on a regular basis and it's still fine. Come on guys, let's worry about performance, not elegance!

 

[Farmerford]

Many years ago I was an engineer in a metal stamping plant that heated and then stamped metal from sheets of 1/4" to 5/8" thick steel using mechanical and hydraulic presses up to 3,000 tons. It seems to me that Kubota first bent the sheet into the channel shape and then put the curve in the channel in a second step. The only way I know of to prevent the crinkling on the edge would be to form the entire piece in one step in a draw die that forces the extra metal out the edge. Such a die would be very expensive, and an exceptionally large press would be required to handle it.

As for the structural defect, it seems to me that those ripples don't materially weaken the edge that will generally be in compression. And it is entirely possible that the Kubota engineers did not use the lower edge beyond the weld in calculating the necessary strength of the boom. If that is the case, the rippled metal is unattractive, but certainly not a structural defect.

I have three Kubotas and am aware of the shortcomings in each one, from the weak (sometimes nonexistent) power steering in the B-2400 to the cheap plastic radiator screen of the L2900 to the over sensitive HST control of the L4330. But I think it is a stretch to call the wrinkles in the lower edges of those booms a structural defect without making a much more in depth analysis of the stresses that are present.

As for John Deere, they apparently bent channel and then welded it together. Since the bottom of the channel (inside of the curve) did not wrinkle, that means the outside of the curve (top of the channel) must have stretched. So the upper surface of the JD boom is thinner than the lower surface. Is that a structural defect? Only if the engineers did not take it into account is calculating the stresses on the boom.

 

[medicshawn]

I finally looked at my loader today it's brand new and lightly used (10 hours). Mine has some waves but I wouldn't have noticed it if someone hadn't pointed it out. I plan to have my tractor for quite a while and won't lose any sleep over the wrinkles.

 

[lawn_king]

Many years ago I was an engineer in a metal stamping plant that heated and then stamped metal from sheets of 1/4" to 5/8" thick steel using mechanical and hydraulic presses up to 3,000 tons. It seems to me that Kubota first bent the sheet into the channel shape and then put the curve in the channel in a second step. The only way I know of to prevent the crinkling on the edge would be to form the entire piece in one step in a draw die that forces the extra metal out the edge. Such a die would be very expensive, and an exceptionally large press would be required to handle it.

As for the structural defect, it seems to me that those ripples don't materially weaken the edge that will generally be in compression. And it is entirely possible that the Kubota engineers did not use the lower edge beyond the weld in calculating the necessary strength of the boom. If that is the case, the rippled metal is unattractive, but certainly not a structural defect.

I have three Kubotas and am aware of the shortcomings in each one, from the weak (sometimes nonexistent) power steering in the B-2400 to the cheap plastic radiator screen of the L2900 to the over sensitive HST control of the L4330. But I think it is a stretch to call the wrinkles in the lower edges of those booms a structural defect without making a much more in depth analysis of the stresses that are present.

As for John Deere, they apparently bent channel and then welded it together. Since the bottom of the channel (inside of the curve) did not wrinkle, that means the outside of the curve (top of the channel) must have stretched. So the upper surface of the JD boom is thinner than the lower surface. Is that a structural defect? Only if the engineers did not take it into account is calculating the stresses on the boom.

Well said farmerford! When i start hearing about catastrophic failures, on 724's i will worry!