Homemade Backhoe Specs Needed

[andyfletcher]

I'm thinking of building a homemade 3PH backoe out of 4" X4X 1/4in box steel. Would that be thick enough? My gusset plates would be 3/8in plate, drilled for 1in cylinder pins.

I also notice that most of your main booms are simply angled downward, and at the point of the bend you guys don't bother with articulating it here and instead simply weld on steel plates to attach the two cylinders, one for the boom pointing back, and the other for the forward arm.

Wouldn't it be better to have a working split boom, then you can work closer to the tractor and in tighter spaces?

Also I was thinking of simply using threaded 1 1/2in square thread rod for the outrigger pads, saving me a spool.

On gang spools, what order is best side by side. Bucket next to forward arm, then boom, then swing cylinder?

My tractor is 9GPM, and my 3PH is powered by an internal 3in piston(IH424), so I know right away a 3in cylinder would be too slow for a backhoe with this pump. Should I stay with cylinders with smaller pistons thereby giving me a faster operation? Say, 2in cylinders and less?

Rodded cylinders are cheaper, are they OK for this job?

The boom cylinder would need to carry total weight plus earthload, plus pressure applied by the forward cylinders, should I use a larger cylinder for it?

Thanks for the help.

Fletch

 

[Paddy]

Fletch,

I have an old Ford 758. I bought it "worked hard and put up wet". I'm in the process of rebuilding it. The material; 5x5" for the main section and 4x4" where the bucket is attached. Mine has 2" cyclinders for all except the main boom and it's 2 1/2".

Control levers from R to Left.

R Out rigger
Curl- Bucket
Forward boom
Boom, main
Swing left
Swing Right
L out rigger

Sorry my names are non-standard. The middle 4 are often tied together with joy sticks. This allows for the Right joy stick to be pulled back and to the left to do the dig op. the left joy stick is pulled back to lift the main boom, then to the left to swing left. I hear there are mainy ways to setup the controls.

You will need the out riggers. They save a lot of stress from the tractor. Also, use a PTO pump/tank

good luck and keep us posted

patrick

 

[dfkrug]

That's a lot of questions. I built a CADDigger 728 10 y ago and it is thicker in some areas than a manufactured hoe, due the use of standard shapes. A 4x4x1/4 boom and dipper stick may be more than adequate, depending on the length of each and the moment arms you design for the cylinders. Factory hoes of the 6-8 foot digging depth often use only 3/16 thick dipper sticks, but they often build stronger box sections, rather than use square tubing.

As for hydraulics, you only need 4-5 gpm to operate a 2 3/4 to 3" cylinder fast enough. I have measured it and timed it for my CADDigger and my current factory Prairie Dog Diggers. Always use your tractor hydraulics if you can.

 

[john_bud]

Andy,

You probably want to beef up the boom. Where the pins go thru add some side plating and weld on DOM tubing to hold the bushings. Might want to use 4x6? The dipper stick should be ok. Make a 4 point mount to the tractor with a full underframe if you can.

You really don't want to economize and kill your self! Use the stabilizers. To dig a straight hole you have to level the hoe (and tractor). Even if your design worked at providing stability, ever try and screw jack a tractor level 20-50 times a day? Ever move a hoe with the stabilizers down? Happens all the time. Think your screws will hold up to that abuse? How about when you hit a hard spot and the tractor shifts? Press a hyd control or pull out a Big Azz wrench and screw jack your self level... I know what I would want to do! Then again, you may have stronger arms than me!

Ford 723 backhoe controls as sitting in the hoe seat facing the hoe, from the left;

Dipper stick
Boom

Offset and shorter levers
Left stabilizer
Right stabilizer

Bucket curl
Swing

Set the spools up so that pushing the lever away from you makes the arm / bucket move away. So moving the dipper stick lever to the rear, moves the dipper stick out/up. Same for the boom. Moving both in at the same time (and curling the bucket) brings everything back and down and fills the bucket. So, you also have to be able to have simultaneous operation of each spool. Mount the cylinders so extending them is done to dig.

If you are making an 8' or smaller hoe, 2 1/2" with 1 3/8" rod is probably a big enough cylinder.

Have fun!
jb

 

[MossRoad]

Andy,
I am in the process of gathering the information that I need to build a backhoe for our Power Trac. Here is a link to a discussion that we are having in the Power Trac forum right now.

Also, here is a link to a page at Vintage Farm Plans that has a page for a portable backhoe. There is a free set of plans there in PDF format. There are two files to download. The plans would be a good reference for a starting point.

Hope this helps and good luck with your project. /forums/images/graemlins/laugh.gif

 

[heehaw]

why do you say to use the tractor hydraulics? i always thought having a separate pto driven pump would be best?
heehaw

 

[dfkrug]

This is a big discussion in itself. In brief, you have a complete hyd system with filters, pump(s), reservoir, and optional valves with the tractor. It hopefully gets regular maintenance. It generates plenty of flow and pressure. I think PTO pumps are available because old tractors did not have the necessary flow and it was a way for b/h vendors to sell you a turnkey system, without having to show customers how to plumb remote hyd to a thousand different tractors. A PTO system will run at least $500 and usually they don't get maintained.