Backhoe Design Ideas

[charlz]

Metal Supermarkets will cut your order etc. not sure if they ship though. There is one here in Boise and it looks like the next closest to you is SLC.... probably not worth the drive either way unless you are already headed there anyway.

 

[J_J]

Iplayfarmer.

I would recommend that you use the 1/4 wall tubing. I would also beef-up the connecting joints with 1/4 or 3/8 in steel/ Otherwise, around each pin area, you would have the 1/4 in wall of the tubing, plus the added stiffness of the 3/8 steel . If it is going to bend or crinkle, it will do it at these places. My front hoe is mostly built, just waiting for some small stuff, and trying to figure out the 180 swing. I have posted some pictures before.

To slow down the hydraulics, just add a ball valve, and adjust it for the speed you desire. That way, you can run the engine for max breakout force, and swing at a slower rate.

 

[Iplayfarmer]

Iplayfarmer.

I would recommend that you use the 1/4 wall tubing. I would also beef-up the connecting joints with 1/4 or 3/8 in steel/ Otherwise, around each pin area, you would have the 1/4 in wall of the tubing, plus the added stiffness of the 3/8 steel . If it is going to bend or crinkle, it will do it at these places. My front hoe is mostly built, just waiting for some small stuff, and trying to figure out the 180 swing. I have posted some pictures before.

To slow down the hydraulics, just add a ball valve, and adjust it for the speed you desire. That way, you can run the engine for max breakout force, and swing at a slower rate.

Thanks for the input. I'm hoping to go get some of the steel tomorrow.

I've been watching your build in conjunction with MossRoad's. You've got a good project.

 

[Iplayfarmer]

I changed my mind about buying steel today. I got to looking at my schedule, and I won't be able to visit my brother-in-law and his plasma cutter for another two weeks. There's no benefit to getting the steel early, and if I wait I can still change my plan when inspiration strikes.

 

[Iplayfarmer]

I nearly ruined the whole plan today. There was a International 3082 backhoe attachment for sale at a good price, and I was thinking about buying it. I'm still trying to convince myself that my little 15 HP tractor could handle it, but I'm pretty sure it won't. That's one of my main reasons for wanting to build my own... I want something that fits this tractor as perfectly as possible to minimize the stress on the tractor.

The attachment didn't come with a pump, and it's a 3 point. I'd have to put some money into it and do some modifications on it anyway. I think I did the right thing to pass on it, but I'll be second guessing the decision clear until this home-built one is finished.

 

[JoelD]

I would expect this to be a classic hombebuilt question, build from scratch or modifiy something existing.

At least with stick built you can design from scratch exactly the way you want it.

Good luck,
Joel

 

[Iplayfarmer]

I would expect this to be a classic hombebuilt question, build from scratch or modifiy something existing.

At least with stick built you can design from scratch exactly the way you want it.

Good luck,
Joel

If it had come with the pump and seat, I'd have probably bought it on the spot and then kicked myself later when I realized that it would dwarf my poor little tractor.

 

[skidsteer.ca]

I find the toughest part about these projects is by the time you use the material you think would be strong enough, the over all weight of the unit far exceeds what you hoped. 1/4" thick sounds good for the boom strength wise, but I'm not sure it is that thick on my 709 bobcat hoe, Of course the size of the box and the length of the gussets play a large roll in strength.

I would encourage you to find the weights for all the material you plan to use (especially for the boom) and calculate the total weight.

My 709 also has a 9' dig depth (which I though you said you planned for) but used more like a 3" cylinder bore and works good with flow in the 10 to 12gpm range. It weights @ 1500 lbs and is attached to a 4700 lb machine.
Ken

 

[Iplayfarmer]

I find the toughest part about these projects is by the time you use the material you think would be strong enough, the over all weight of the unit far exceeds what you hoped. 1/4" thick sounds good for the boom strength wise, but I'm not sure it is that thick on my 709 bobcat hoe, Of course the size of the box and the length of the gussets play a large roll in strength.

I would encourage you to find the weights for all the material you plan to use (especially for the boom) and calculate the total weight.

My 709 also has a 9' dig depth (which I though you said you planned for) but used more like a 3" cylinder bore and works good with flow in the 10 to 12gpm range. It weights @ 1500 lbs and is attached to a 4700 lb machine.
Ken

Thanks for the input. Is there a place on your hoe that you could measure the actual thickness? It would be nice to know.

I'm also thinking that with the side panels on the boom, I'd have a lot of added strength there.

Has anyone out there busted or bent a backhoe? Where did it break?

 

[Danno1]

.

My dipperstick has a dent in it just above the bucket. Looks like someone curled it too far w a large rock in it. Doesn't affect the operation at all.

Don't know the wall thickness. I'll look and see if it's possible to measure.

.

 

[Iplayfarmer]

Now that summer is more or less over, I'm back to designing again. Since the last post I lost all of my files related to the backhoe. I had been working off of an SD card so that I could design on any one of three computers that I commonly use. It's just another lesson in backing up files I guess. The bright side is that I'm going back through it again and fine tuning some of the stuff that wasn't quite right the first time.

My question right now is about stabilizers. A lot of the cheap home built plans use manual stabilizers. I'm sure that the hydraulic stabilizers are nice to have, but the question is if they're worth it for this size of a backhoe. I already have most of the components, so I'm not talking about monetary costs, I'm talking about complexity and weight costs. I only have a 5 spool valve, so I'd either have to get a splitter for the fifth spool to controll the two stabilizers independently or I'll have to add another valve to the hydraulic circuit. Hydraulic stabilizers are going to weigh more too.

Thoughts?

 

[dfkrug]

I only have a 5 spool valve, so I'd either have to get a splitter for the fifth spool to controll the two stabilizers independently or I'll have to add another valve to the hydraulic circuit.

You can use one valve for both outrigger cyls, connected in parallel. I
operate mine simultaneously most of the time anyway. It puts equal
lifting force down, which is usally a good thing.

As for adding weight, that is not necessarily a bad thing.

 

[MJPetersen]

The only time that I can thing when you would need different pressure to the two stabilizers is if you are digging on a side hill and need to level things up. But that would not be that frequent of occurrence. Most often they are used together.

Mike

 

[Iplayfarmer]

The only time that I can thing when you would need different pressure to the two stabilizers is if you are digging on a side hill and need to level things up. But that would not be that frequent of occurrence. Most often they are used together.

Mike

So if I was on some kind of a side hill would there be a way to do it if I had both outriggers on the same valve?

 

[MJPetersen]

So if I was on some kind of a side hill would there be a way to do it if I had both outriggers on the same valve?

Not that I can think of--both stabilizers would exert the same pressure down, but that would not "level up" the machine.

Well now you could do it this way. put the stabilizers down--swing the boom down hill--put the bucket on the ground--lift stabilizers off ground--push down with boom and pick the hoe up until it is level--then drop the stabilizers down. It is a bit of a process but you could do it.

Mike

 

[Iplayfarmer]

Not that I can think of--both stabilizers would exert the same pressure down, but that would not "level up" the machine.

Well now you could do it this way. put the stabilizers down--swing the boom down hill--put the bucket on the ground--lift stabilizers off ground--push down with boom and pick the hoe up until it is level--then drop the stabilizers down. It is a bit of a process but you could do it.

Mike

I don't mind a "bit of a process" if it's the rare occasion. I do want to make sure that I can do it, though. I'm liking your idea.

Sounds like I get the best of both worlds... Hydraulic stabilizers without the added complexity of additional hydraulic valves. I suppose worst case scenario, I add a valve later.

 

[radioman]

the stablizers helps the holding force from moving forward as well. Its ture levling off the BH is a good thing since most diggin is in uneven surfaces anyway.

 

[Iplayfarmer]

Okay, here's a potentially dumb question... If I have both outriggers on the same circuit, would they not still move even with the valve closed? Without check valves, couldn't fluid flow between the cylinders such that one side could be pushed up by allowing the other side to push down.

The result here would be that with the back wheels off the ground the tractor would just sway like a see-saw.

 

[dfkrug]

If I have both outriggers on the same circuit, would they not still move even with the valve closed? Without check valves, couldn't fluid flow between the cylinders such that one side could be pushed up by allowing the other side to push down.

The result here would be that with the back wheels off the ground the tractor would just sway like a see-saw.

With both cylinders plumbed in parallel, and the valve closed, you are
correct that oil can move between the two cyls if there is a pressure
change on the outriggers. This is exactly what happens with my b/h
thumb and my 4n1, which are plumbed this way.

In your situation, if you lifted your rear wheels off the ground with the
outriggers, then lifted a big weight with the hoe turned at 180-deg, you
could cause some tilting. But you should not be lifting your wheels off
the ground anyway. That type of hoe usage is more for purpose-built
TLBs.

 

[Iplayfarmer]

With both cylinders plumbed in parallel, and the valve closed, you are
correct that oil can move between the two cyls if there is a pressure
change on the outriggers. This is exactly what happens with my b/h
thumb and my 4n1, which are plumbed this way.

In your situation, if you lifted your rear wheels off the ground with the
outriggers, then lifted a big weight with the hoe turned at 180-deg, you
could cause some tilting. But you should not be lifting your wheels off
the ground anyway. That type of hoe usage is more for purpose-built
TLBs.

But still, in that configuration, the stabilizers aren't going to really stabilize much.

Right?