how to build your own custom backhoe subframe

   / how to build your own custom backhoe subframe #141  
Looks good Tom. Don't think I can add anything to what has already been said. Good luck, and welcome to the forum.
Although I might add that I never had any issues with my LiTW backhoe rigid top link with the dozer, and I did a lot of heavy right-angle work with it.
 
   / how to build your own custom backhoe subframe #142  
Thanks all,

I didn't notice before but the drawbar on the tractor is bolted to the gear box with 6 3/4 inch metric equivalent bolts. (see pic). I am going to weld top and bottom plates with gussets to this drawbar attachement over to the 2x4/1/4 ladder frame as well as use the 3 point hitch pins. This brings the tractor mount much closer to the hoe. With this I am how really comfortable now with welded triangulated mounts from the area around this drawbar to the backhoe frame in place of the top link but I will use the top link anyway in addition to the welded triangulated sub frame braces because I have it. drawbar.jpg

I have also included a pic of my broken top link (to prove I am not lying :) ).toplink.jpg
 
   / how to build your own custom backhoe subframe #143  
Just so you don't feel alone, I had a top link fail the same way, American made and hydraulic too. But it was my fault for using too small of a cylinder.

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   / how to build your own custom backhoe subframe #144  
Not many tractor owners are willing to go thru the process of making a
custom subframe to mount a backhoe attachment securely to their tractor.
I want to encourage anyonewho is reasonably handy to consider doing
this....it is very rewarding, and you can endup with a TLB setup that
comes close to what you would get if you had a factory-integrated
Tractor-Loader-Backhoe. A custom subframe can be built BETTER than an
add-on subframe from a maker of hoe attachments. More on that later.

I get asked to build a subframe for someone else's tractor now and then. I
never take them up on the offer, but I am happy to show them how I do it.
I have helped some folks long distance, but that is difficult. I want to use
this thread as a go-to place for those considering the fabrication of their
own subframe. In my approach to design and fabrication, I always want to
have both the hoe and the tractor here: measure 3 or 5 times, and cut only
once, hopefully. I have learned a lot about backhoe attachments and
subframes by owning and making them, and by analyzing the many samples
I have seen. I have a large database of hoe attachment specs, but I
am always looking for more data and new ideas.

In this thread, I will show the process I went through to design and fabricate
a subframe to attach a Prairie Dog 7.5 backhoe attachment to a John Deere
4300 tractor. I will use this and other examples of subframes to illustrate
different design approaches. Comments and questions are welcome.

But first, I want to discuss the basics.

What is a subframe? It is a structural member(s) that is rigidly tied
with welds, bolts, or pins to the main structure of the tractor. The
subframe rigidly transmits the forces from the implement to multiple parts
of the tractor's structure. By distributing the forces caused by the
implement, the tractor is protected from excessive concentrated forces, including excessive tension as well as destructive bending moments.

Subframes are used as a superior way to mount a backhoe, instead of
using the Three Point Hitch (TPH). There are many cases where a
Category 1 TPH has been used to successfully mount a backhoe.
There are also numerous documented cases where TPH-mounted hoes
have broken the toplink mounts, or cracked tractors in half. That is
no news to TBN members. Subframe-mounted hoes can also provide a
better integrated tractor with the hoe mounted much closer in to the
rear of the machine. A closer-mounted hoe will increase the minimum
departure angle, which is a fancy way of saying it won't hit the
ground as often when driving through a depression, or onto a trailer. Some
off-the-shelf subframes do not mount the hoe any closer than a TPH mount,
however. A closer-in hoe mount will also improve a tractor's drivability.
If a large weight it mounted far from the center of gravity of a tractor,
it will have what is called a high polar moment of inertia. This inertia
will resist changes in steering input.

In the first photo, I show the parts that comprise a 3PH hoe attachment
mechanism. On the left are the parts that are permanently bolted to the hoe.
The other parts comprise a much stiffer toplink, and brackets to keep the
lower 3PH arms (not shown) from rising. The second and third photos show
the same tractor on the 3PH, and on a Woods subframe, respectively. This
early Woods subframe does not mount the hoe any closer to the tractor
than the 3PH mount does.

Next: subframe types
Is there a kit made for a JD5105? I found this ARIMain - WEINGARTZ

my goal is to safely use a small backhoe attachment.
 
   / how to build your own custom backhoe subframe
  • Thread Starter
#145  
Tractor Data is not clear on the JD 5105: does it have CAT 1 or CAT 2 three point hitch?

Anyway, if you want to convert the Kubota subframe you found, that is fine. You can run it off the AUX valve work ports, if you have AUX SCVs, or via a power beyond connection. The RV on your backhoe attachment will limit the pressure to 2500psi, since your tractor puts out 2800. If your JD dealer has a power beyond kit to support a backhoe, it is not listed on the site you linked.
 
   / how to build your own custom backhoe subframe #146  
MOST of the green/yellow tractors below about 80HP are contract built in South Korea.
Those colors CO$T a lot, so if you can find the non-JD eqivalent tractor (i.e. different paint job) then the answer is likely "Yes and for a lot less"
 
   / how to build your own custom backhoe subframe #147  
Hello gents, cracking thread this.

Is anyone able to offer any advice about backhoe frame mounts on my B1400. i have a small italian side shift frame to go on it.

I am considering hanging the rear of the sub frame on the 4 bolts on the rear axle. are these 4 bolts strong enough to take the loads?

The sub frame will then continue forwards and the front will bolt onto the loader arms. I'm hoping to let the loader frame spread the loads about.

Is this feasible?

Many thanks
 

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   / how to build your own custom backhoe subframe
  • Thread Starter
#148  
Is anyone able to offer any advice about backhoe frame mounts on my B1400. i have a small italian side shift frame to go on it.
I do not know the B1400. Are you in the US? How small is the hoe you have?

As for the strength of those plates on the rear axle, it is hard to say. How are the plates mounted to the axle housings? Those are pretty small-looking bolts, but at least the forces would be in shear. Is everything in that area steel?

The Kubota B-series, except for the B20/21/26, are all pretty wimpy in the rear axle department. Kubota did have some small K-series hoes they sold for those early units, with subframes. About 6-ft dig.
 
   / how to build your own custom backhoe subframe #149  
I do not know the B1400. Are you in the US? How small is the hoe you have?

As for the strength of those plates on the rear axle, it is hard to say. How are the plates mounted to the axle housings? Those are pretty small-looking bolts, but at least the forces would be in shear. Is everything in that area steel?

The Kubota B-series, except for the B20/21/26, are all pretty wimpy in the rear axle department. Kubota did have some small K-series hoes they sold for those early units, with subframes. About 6-ft dig.

Thanks for taking the time to reply dfkrug. The B1400 is a grey import machine. 19hp. I can only find very limited information on the tractor. I do have a manual which suggests fitting a backhoe can be done (doesn't say how) it also says the max 3 pt lift is 300kg. The backhoe is an old sigma 3 pt machine. it was originally 330kg, but ive stripped quite a bit of weight when I removed the hydraulic tank and some surplus panels that aren't going back on. at a guess its about 250-280 kg now.

The plate is 100mm x 12mm mild steel which is secured to the axle housing with 4x M12 bolts. the bolts are graded 8.8 and are 40mm long of which about 26mm is threaded. As far as I'm aware the axle housings are cast iron.

I do have an option to add more support above and around the front of the axle if required. Ive included a few more pics of my setup so far.

I'm after a very close coupling. How much clearance should I leave between the rear of the ag tyres and the backhoe posts?

Really appreciate your wisdom because I have only recently upgraded my welder and while ive done enough to ensure im producing good welds, I am by no means experienced in this field.

Dan
 

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   / how to build your own custom backhoe subframe
  • Thread Starter
#150  
Are you sure your hoe is only 600#? Any side-view pix of it, with something nearby for scale? That is a pretty small Kubota.

I am for close-coupling the hoe to the tractor, for sure. I see you have the rice paddy tires. You can get away with as little as a finger's-width spacing there, but it will require walking on the rear tire to mount the hoe seat.
 
 
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