Diamond Shape Sub-Frame for LW-8 Backhoe

[3RRL]

Now that I have the lower receivers reinforced, and the front support tubes installed, I got to making the upper backhoe subframe. They are shown in the first photo below. BTW, all the holes are bored through the thick wall rectangular tubing and then have either DOM tubing (drawn over mandrel) welded in for the holes, or solid steel inserted for reinforcement. The lower receivers on the tractor have solid steel on the inside of the rectangular tubing and the mating ones on the backhoe have DOM. An example of the steel inserted is shown when making the bolt on end of the upper backhoe frames shown in the 2nd photo below. Solid #2 steel (4130) is welded into the rectangular tubing.

The lower backhoe support frame (last photo below) are welded to the bottom of the backhoe. The other end is connected to the receiving supports on the tractor via those 1" diameter pins. Those are the only place where this subframe is pinned.

 

[3RRL]

OK, that's all there is to it.
Below are photos of the backhoe subframe completed. I had to fixture up every connection before and during all the welding to keep a perfect alignment. I had to add some rectangular tubing and plates to both the upper and lower backhoe connections to make them support the hoe properly. Other than that, it came out pretty sweet.



Note also that both upper and lower frames are cross connected vertically and horizontally to each other with 1-1/2" diameter round tubing. This pretty much keeps the whole shebang square under load. When connected up to the tractor, the diamond shape is completed and further bracing throughout the tractor and backhoe is achieved...front to rear.

 

[3RRL]

So here is how the backhoe is connected up to the tractor.
The first photo below shows the upper connection bolted together. It also shows the front strut support going down to the front FEL support. The second photo shows the lower connection pinned together. I took it outside for a tryout after that.



You can't believe how worried I was about line up before I connected it up.
I was very pleased when I backed the tractor up to the backhoe and the lower connections lined up to be pinned together easily. Then I used the backhoe to push itself up, rotating up on the lower connecting pins until the upper bars touched the ROPS (it cannot rotate up any further). I then screwed in the 3/4"-10 bolts and the subframe was 100% connected.

 

[3RRL]

I wanted to share a couple more things.
Before I put the backhoe back together, I machined out the plate covering the valve. There were "+" shaped clearance slots for the control handles in it, making it impossible to control the backhoe with simultaneous movements such as pulling in the dipper stick and curling the bucket at the same time. Or extending the boom and swinging at the same time. Boring out that plate made it act like a regular backhoe. And of course, my dear wife Loretta helped me through the whole project and did all the paint touch up for me, as usual.

 

[3RRL]

There were a couple last things to do before it was ready to dig.
First, I had to secure the PTO pump to keep it from spinning (first photo). Second, because I do not use the lower links, I had to make sure they didn't creep down onto the hydraulic tank which is mounted on the backhoe. I made a bar which holds the lower links in position ... not only up, but spread the right distance apart so they will clear properly when backing the tractor up to the backhoe. I put this on before I connect the PTO pump, and then back in the rest of the way for the hook up.



After that, I took the tractor out and started to dig a 60' long trench for the water and electrical lines for Loretta's garden shed. That's one of the projects we will be working on in the next few months.
Perfect timing...
Rob-

 

[Eagleview]

I wanted to share a couple more things.
Before I put the backhoe back together, I machined out the plate covering the valve. There were "+" shaped clearance slots for the control handles in it, making it impossible to control the backhoe with simultaneous movements such as pulling in the dipper stick and curling the bucket at the same time.

I'd thought you'd gone AWOL Rob .

You have me a little confused here , I take it the controls you have are x+ axis controls and not just + ? They would have 8 or more hydraulic hoses going to them and not 4 ?

Great job on the frame , it's good to see someone who knows that strength is not in weight , but in fabrication .

 

[mjncad]

As usual Rob, you did a great job.

 

[3RRL]

Hi guys and thank you, always good to hear from you guys.
I'm still kicking but have been mostly reading and not posting much.

Iron Horse, there are 14 hoses coming out of that valve for the cylinder controls, including stabilizers and in and out (return to sump). What I was talking about was that the plate covering the backhoe valve was machined (or punched die) with slots (see photos) to allow the control handles to move only forward and back and sideways ... not allowing the handles to go into a 45 degree angle where two functions can operate simultaneously. In other words, the slots only allowed the handle to be pushed straight forward and back, and you had to get out of that slot to move the handle sideways. So the slots only allowed you to move one cylinder at a time, not two.

For example, when moving the dipper stick, you could only move it out and in.
If you wanted to curl the bucket, you had to get out of that slot and move the handle into the sideways slots. Then that allowed you to curl the bucket in and out. By removing the + shaped slots, I can now move the handles at a 45 degree position which allows simultaneous movement of the bucket curl and dipper stick. I know I've been redundant in trying to explain, but I hope I've written that clearly enough so as not to be confusing?

Below are photos of the hoses and valve control handles.
The 2 with slots are for the stabilizers, and the other 2 are to operate the boom, dipper stick and bucket. Those are the ones that now have a circle for simultaneous movement instead of the "+" shaped slots that used to be there as shown in the middle photo below.

 

[3RRL]

However, I did not come up with the idea.
I believe Tim Wales, long time member here, was the first (if I remember correctly) to do that to his backhoe plate. Having said that, and having owned the Nardi backhoe for almost 5 years knowing it should do that, I think I would've attempted it anyway. The valve, however, is not nearly the quality and smoothness of the Italian Nardi backhoe.

I don't know if you noticed or not, but some photos show the huge Kama fronts and rears off the ground in one of the last pictures. This subframe is so rock solid that even the slightest movement of the backhoe is absorbed by the subframe. In other words, there is Zero play in it. And I mean absolutely ZERO play! And once the backhoe is up on it's stabilizer feet, it feels rock solid when digging.

When I push one of the stabilizers down, or the boom down, the entire tractor moves with it.
My other subframe for the Nardi backhoe always allowed the backhoe to move independently of the the tractor for a few inches before that subframe tightened up. That shows (to me) how rigid this new subframe turned out. It not only solidifies the backhoe subframe, but has solidified the FEL subframe as well (through the front struts connection).

So it was a worthwhile investment for me in more than one way.
I'm very confident that there will be no damage to my tractor either from backhoe or FEL use now.

 

[EddieWalker]

Another great project. I like the way you engineer stuff and explain why you do what you do. Nothing is random, and everything has a reason for why it was done that way!!!!

Now that you have the bigger hoe, when does the thread on your pond begin? LMAO

Eddie