Mini Skid Brush Mower Build

[leotech]

Hi Everyone,
I've been trying to wack down thistles, small trees, > 2", and field grass, 5-8ft high. I did notch a old 5hp mower in the front with my plasma cutter and made it into a brush mower. It did a great job but limited to 20" width. It's weird to be in a valley of thistles.

My plan is to build a hydraulic brush mower attachment for Ditch Witch SK500. Track width is 42" so a 48" width is what I'm expecting to cut. Based on the specs of the Aux circuit, it is 12gpm 2500PSI.

questions I have is the following.

Direct Drive off hydraulic motor or Right angle Gearbox to hydraulic motor?

RPM of most brush mowers? What size motor to start looking at?

Since I'm trying to build a "standard" brush mower, using standard parts, I don't want to get a gearbox that is odd size. Other makes and models I can steal from?

For the blade, a 24" circle with 2 to 4 blades on pivot point.

I already have a blank quick mount plate, plasma cutter, Miller 211 MIG setup with Flux-Core .035".


Thanks,
Curtis

 

[bcp]

Blade tip speed thread:

http://www.tractorbynet.com/forums/owning-operating/91240-rotary-cutter-bladt-tip-speed.html

 

[leotech]

Since I'm not planning on doing golf course finishes, it doesn't need to be that fast right?

 

[SSdoxie]

The hydraulic cutters I have seen use a gear box and the motor is coupled to it where the PTO is on tractor version. I think you would be well ahead to look for a decent used 48" pto cutter the convert it to your loader mount and hydraulic drive.

 

[woodlandfarms]

Check out power-Trac.com for ideas.

Our mowers are direct drive 3 blade affairs, I think 800 rpm motors.

Not an easy build with balance being so important.

I think finding an old brush hog with a locked up gearbox would be the a ticket

On our directdrive there is a lovejpy I between.

 

[J_J]

I agree with SSdoxie in getting a 48 in bush hog and adding a hyd motor that will run at 540 to 600 rpm to the gear boxshaft and add your skid steer plate to the 3pt section, or get the adapter to go from skid steer to 3pt attachments.



Remove the wheel on the back and cut about a 6 in slice off the back side and make it into a hinge flap.

Raise the flap to vertical when cutting, and when not cutting, lower the hinge plate and cover the blades.

Maybe something like this.

http://www.brushwolf.com/

http://www.youtube.com/watch?feature=player_embedded&v=S72dXWzYdeI

http://www.youtube.com/watch?feature=player_embedded&v=S72dXWzYdeI

Right Angle gear boxes.

http://www.surpluscenter.com/sort.asp?catname=powerTrans&keyword=PGRA

 

[brokenot]

No matter which way you choose to go with your home-built cutter, take a look at the factory built models for examples of what drive motors they use. I'd think they *have to* be using motors with internal reliefs, (or a separate manifold with reliefs), because when you turn the mower's oil supply "off" with the blade(s) already up to speed, the rotating assembly is going to go from spinning to not spinning pretty quickly.

That will be hard on things. Something to do with Newton's First Law of Motion....

 

[3238dpw]

Here are some links that might help

http://www.tractorbynet.com/forums/build-yourself/183482-homemade-hydrolic-brush-cutter-land.html

Brush Cutter Project - TractorByNet.com

[ame=http://www.youtube.com/watch?v=YRlXeLFUX68&feature=channel&list=UL]MVI 3284 - YouTube[/ame]

[ame]http://www.youtube.com/watch?v=_-BpZk3X_sI&feature=plcp[/ame]
[ame]http://www.youtube.com/watch?v=CAr2R29UpN8&feature=channel&list=UL[/ame]


There are other links I have but thay are on other forums and I believe we can not link to other forums. If you PM me I will send you the links

 

[Derik]

I am very interested in this thread. This is something i have been thinking of doing for a while now. We have a toro dingo 525 and a dw sk650. We either sub out brush mowing or for small jobs rent a billy goat brush mower.

 

[leotech]

I searched far and wide for a mower deck but could not find any in my area that were in ok condition or reasonable price.

I ordered the following items for my build.
1. 40hp gearbox 1:1.45
2. stump jumper plate
3. blades
4. blade bolts

Next is sizing hydraulic motor.

Since I only have 8gpm @ 2500psi, I'm somewhat limited in sizes. I've calculated in order to have a input speed of 2500rpm for output of around 3600rpm, I would need a high speed motor of around 0.5cu in.
Surplus Center - 0.580 cu in PARKER MGG20025-BB1B3 HYD MOTOR

It seems a bit fast so I might size the motor for a 1.0cu in for half the input speed for output spindle of 1800rpm.

Thanks,
Curtis

 

[aczlan]

There are other links I have but thay are on other forums and I believe we can not link to other forums. If you PM me I will send you the links

As far as I know, we can link to other forums...

Aaron Z

 

[leotech]

Did more calculations on motor size for final drive RPM.

1:1.47
Output = 1000rpm
Input = 680rpm
Motor size = 2.7 cu in
Surplus Center - 2.5 cu in WHITE 255040F3DD22AAAA HYDRAULIC MOTOR

Output = 1500rpm
Input = 1020rpm
Motor size = 1.8 cu in
Surplus Center - 1.93 cu in CHAR-LYNN 129-0004 HYD MOTOR

 

[Derik]

I am looking forward to seing how this progresses.

 

[SSdoxie]

No matter which way you choose to go with your home-built cutter, take a look at the factory built models for examples of what drive motors they use. I'd think they *have to* be using motors with internal reliefs, (or a separate manifold with reliefs), because when you turn the mower's oil supply "off" with the blade(s) already up to speed, the rotating assembly is going to go from spinning to not spinning pretty quickly.

That will be hard on things. Something to do with Newton's First Law of Motion....

A simple way to make an over run valve is use an inline check valve similar to this. Surplus Center - 3/8" NPT 10 GPM CHECK VALVE 65 PSI CRACKING, Tee it into both lines going into the motor so the flow through it is from return line to input (pressure line). The working pressure will keep it close while running and when shut off the spining blade will open the valve so motor can coast. Use a high pressure valve and it will act as a coaster brake.

 

[leotech]

Thanks for the link. I was looking for check valves.

 

[tmc_31]

Hi guys, I have been reading this thread and others about building a brush cutter as I am interested in buying or building one for my-self. Given the price of these attachments, I am leaning towards building my own. I will be using it on a NH L190 with 21 GPM at 3000 PSI. I too am concerned about what is happening in the hydraulic circuit when you shut off the flow to the cutter. My plan at this point is to use a char-lynn 104-1024 motor and a 75 hp gear box with a 1:1.47 ratio. If my calculations are correct, I should be getting a little over 16,000ft/min blade tip speed and 318 ft/lbs of torque.

Has anyone thought about putting a overrunning clutch between the motor and the gearbox? Seems to me that this would alleviate any concerns about the blade coast upon shutdown loading up the hydraulic circuit.

Also, My skid loader has no provisions for a case drain. Most of the hydraulic motors in this class seem to require it. Has anyone retro-fitted their tractor or skid loader for a case drain? If so, what is involved?

Has anyone tried to use one of these cutters on a Tractor. So far I've only seen them used on skid steers. Looks like a tractor with a quick-tach on the front and front remote hydraulics would work. I have both of these on my TN70D.

Thanks,

Tim

 

[Farmerford]

Here are some pictures of something similar I built several years ago. For some reason (my ignorance) I can only get a couple of the pictures to attach. The rest of the pictures are replaced by a "?". If anybody is interested in seeing them and can tell me what I am doing wrong I will try again to post them.

 

[XxLT250RxX]

Here are some pictures of something similar I built several years ago. For some reason (my ignorance) I can only get a couple of the pictures to attach. The rest of the pictures are replaced by a "?". If anybody is interested in seeing them and can tell me what I am doing wrong I will try again to post them.

Here is the link to your thread with your pic's. I bookmarked it as I really like it and still intend to copy your design. It's been about 5 years since you posted it. Any advise to potential builders now that you have used it for a while? Also watching the OP progress.

http://www.tractorbynet.com/forums/showthread.php?t=95678&highlight=mower

 

[Farmerford]

LT250R:

Thanks for finding that old thread. I have made some changes to reflect experience of the past five years, mainly in the wheels and in the blades. The machine is a short distance from here and I plan to use it this weekend if the 105 deg heat doesn't keep me by the air conditioner. I will send some updated pictures and explain what I have changed.

Chuck Ford

 

[leotech]

After a few design changes and finally getting to this project, I have the steel ready for welding!