Ditch & Bank Mower Build

[Joee]

Hi guys,

I have been working on this cutter just about all summer. What I thought would be a 2 or 3 week build took on a life of its own. I have reached the point where I need to run hydraulic hoses and finally give this thing a try.

What I need advise on is what size hydraulic hose to use. Going to remove loader and use the joystick to control boom arm. The cutter will be powered by its own hydraulic system using a 21gpm PTO pump and 20 gal reservoir.

How will hose size effect speed and movement of the boom arm? Would ¼ in hose give better control than 3/8 or ½? I need good joystick control so I am not fighting it trying to manage deck movement. I can control all 3 movements from loader joystick.

Thanks all, Joe

 

[ovrszd]

Sorry I can't offer technical answers but I'm sure Mad or some of the other gurus will chime in. Just wanted to say that's a great idea!!! I'm building a PTO log splitter and that would be a great second job for the pump!!! I'll keep an eye on this thread. Good Job!!!

 

[kennyd]

1/4" hoses will be good for the cylinders, the smaller hose will give you slower control as you have already figured out.
If you are turning the blade with a hydraulic motor (I assume you are since you have the PTO pump) then you will need 1/2" hose to the motor to keep the flow rate up and keep things cool. You also may need to add a oil cooler so keep an eye on the temp of the oil.

That looks like a great project and certainly well thought out. Please keep us up to date with lots of pics!

 

[KWentling]

My hydraulic books are all at work I don't work with hydraulics enough to go from memory, but I'm pretty sure you're going to want at least 3/4" hoses for 21 gpm, maybe even 1". I think you're going to need to keep restriction (small hose = friction=heat) to a minimum or you're to have a problem overheating you're oil. I would expect that the pump has 1 1/4" suction and 1" pressure ports? You may be looking at adding an oil cooler to keep you're oil temps under control. Minimum oil reservior to pump gpm is 1-1 as I recall. 2-1 is better. As far as hose size for the cylinders, I'd use the same size that was used on you're loaders cylinders. Nice looking job on the mower. I have given some thought to building one also. I'd be interested in how it works out. Good luck.

Kim

 

[mschech]

Interesting project.
makes me want to mention a project a coworker was hired to build the motor controller for.

Imagine yours... but instead of being on a arm... it has a 30 hp motor and 4 hydralic motors with wheels, 1 at each corner, and a 4' cutting blade.

And a model airplane controller to control throttle and foward/rev on each motor.

Designed for highway bank cutting, should be hitting the market soon.
(prototype was built earlier this year)

 

[Renze]

I checked the pipe recommendation chart lately, when i needed a pipe to directly feed the 4 section valve block of my front loader from the pump, bypassing the tractors built in SCV and 3pt lift valves.

The tractor dealer had only 3/8" and 1/4" hydraulic pipe, i chose the latter which i bent with a manual bender for copper drinking water lines.

The recommendation chart said that the 1/2" pipe could just about handle my 32 liter per minute oil flow within recommended efficiency limits. The return line was recommended 3/4"

Most manufacturers of farm machinery use the smaller lines because of cost, and because most cylinders are used intermittently, unlike a feed line to a front loader valve block, or a hydraulic motor of a mower.



I am thinking of building either a PTO operated bush hog to be operated with my smallest (1,65 m wide) tractor, a 30 hp Zetor 2011, driving BEHIND the fence, or hydraulic driven mounted on an offset arm on the front loader, reaching OVER the fence....

Would 175 bar and 32 liter per minute be enough to drive a bush hog, or would i need a PTO driven hydro pack ?
In other words, what is more likely going to work, the 30 hp tractor shredding saplings and brush with a mower as wide as the tractor (1,65 meter is 5 and a half foot) or the 32 liter. 175 bar oil flow going to cut the same 1" brush with a working width of 3 feet ????

 

[Tom_Veatch]

...
In other words, what is more likely going to work, the 30 hp tractor shredding saplings and brush with a mower as wide as the tractor (1,65 meter is 5 and a half foot) or the 32 liter. 175 bar oil flow going to cut the same 1" brush with a working width of 3 feet ????

My back of the envelope calculations, neglecting less than ideal efficiency in the processes, shows 30 HP applied to a 5.5 feet shredder yields about 5.45HP per foot of mower width.

The hydraulic (32 liter/minute = 0.0109 cu ft/sec, 175 Bar = 2538 psi) unit would generate about 12.5 HP. Applying that to a 3 ft wide strip yields about about 4.17 HP per foot of width.

Based on that, I'd guess the pto driven shredder would be a more effective cutter. But, there's several potentially inaccurate assumptions built into that guess.

 

[srjones]

Hi Joee,

Great project. You've almost built a full backhoe A few questions, though...

Does the arm 'float' or do you need control the height/angle?
Does the mower deck have wheels to adapt to the ground?
What happens if you hit something while traveling forward?

 

[sandman2234]

I bought 1/2 of what he is building, on a larger scale. It was a 5' mower with a hydraulic motor driving the blades. Doesn't looke like it has ever cut a blade of grass. I wanted to be able to run it and the bush hog at the same time, but my tractor hydraulics won't handle it. So sooner or later I am going to put it on ebay and recoup my money (and a little extra hopefully)
It has 4 wheels that ride on the ground all the time, so keeping it level isn't a problem. Hopefully anyone building one of these puts in some sort of shear pin to break, instead of bending the arm.
David from jax

 

[ovrszd]

I bought 1/2 of what he is building, on a larger scale. It was a 5' mower with a hydraulic motor driving the blades. Doesn't looke like it has ever cut a blade of grass. I wanted to be able to run it and the bush hog at the same time, but my tractor hydraulics won't handle it. So sooner or later I am going to put it on ebay and recoup my money (and a little extra hopefully)
It has 4 wheels that ride on the ground all the time, so keeping it level isn't a problem. Hopefully anyone building one of these puts in some sort of shear pin to break, instead of bending the arm.
David from jax

Can you take some pictures of yours and post them??? Joee might benefit from that also. Thanks.