Building a engine powered 4-5ft brush hog

[db556]

Well I let my property get very overgrown, so much that my gravely walk behind(and me) just can't keep up.

I tried trimming the front and back of the deck on a cheap lawn tractor but I had to stop every few minutes to get the chainsaw out for anything over 3/4"

Last summer I dug up a 40" swisher ATV tow mower and it worked OK if I smashed things with bucket of my skid steer, (1980's New Holland L425 with no auxiliary hydraulics) but since it had a solid blade and no stump jumper it stalled out a bunch and I didn't know since I couldn't hear it, skid steer need a new muffler.

My plan is build a engine powered to push it in front of tow it behind my skid steer.

So I'm currently browsing craigslist and marketplace for no too rusty but cheap 4 or 5 ft brush hog.

Now I have some double 5/8" vbelt sheaves that if the engine is turning about 3500rpm should give me about 550rpm "PTO"

Now I thinking how big of a engine to use?

I know tractor and lawn 'tractor' HP don't really match up but at about 5hp per foot I'm guessing about 25HP or more.

So maybe a 25hp kohler command or HF predator engine, or I can dig up a 1600cc VW air cooled or Wisconsin V4D or similar either is about 26-40hp and probably high torque than the lawn tractor engines, but would be more work to either find or setup a clutch for. Where with the lawn tractor engines I can just use a go kart clutch.

Anybody have any thoughts, or have done this before?

 

[ArlyA]

I've designed a similar project and I'd add some comments over time. I like that you are using belts, which would be something to break instead of costly hard to fix parts. Are you going to used angle drive like on regular three point mowers?? I'd use an electric clutch..

 

[db556]

Finding a dual vbelt electric clutch for a 1" or greater shaft might be a problem.
If I go with the 25hp kolher engine, I was thinking of using a linear actuator to tension the belts with a idler.

I think I found a cheapish 5ft ford, sellers going to send me some more pictures.

I have a line on a single port 1600cc VW so thats about 40ish horsepower but I would need to make bearing mount and a splined shaft to mesh with the clutch and and mount for the starter motor. But if I could rig up a clutch lever that would work well.

 

[metalbender]

Funny how rare VW engines have become. I lived and breathed them for about seventeen years.

 

[quicksandfarmer]

Have you thought about using a hydraulic motor and your skid steer hydraulics?

 

[aczlan]

Have you thought about using a hydraulic motor and your skid steer hydraulics?

No aux hydraulics per post 1, therefor that isn't feasible.

Aaron Z

 

[BrokenTrack]

Anybody have any thoughts, or have done this before?

I looked at a forestry mulcher at the local agriculture show and it looked pretty simple.

It would be costly to buy the carbide inserts, but once they were installed, I think a homemade version would be just as good as a bought version.

Like you. my idea was to mount a separate engine to power the mulcher through v-belts. I would have the heavy-duty shaft counter-rotate against the fixed anvil shaft, to trap the debris, and it would be chewed off easily enough. I am not sure how much it would take on as far as sapling size goes, but probably more than a person thinks.

Kind of a simple build really, it just has to be rugged.

 

[Diggin It]

My 3' self propelled uses a 22HP RobinSubaru, and a single V belt with a manual engage lever. But the engine also powers two Peerless Hydro drives.

It'll take down anything it can get over, up to about 3" diameter. Biggest issue is that the drive won't power forward enough to push more rigid saplings over enough to get to the blades. The front lifts and wants to climb those saplings. I've wondered about attaching it to the loader arms somehow to give me more forward push and the ability to lift and adjust, but I'm not sure the loader arms are strong enough to handle any potential twist.

 

[ArlyA]

I think 25hp for a 5ft mower will be to low. Another point is as soon as people get their rough mower out, not cutting anything over 3/4 goes by the wayside. The reason I was looking at electric clutchs so as to give the operator a quick shut off down option in case they find that hidden rock or stump.

 

[aczlan]

I think 25hp for a 5ft mower will be to low. Another point is as soon as people get their rough mower out, not cutting anything over 3/4 goes by the wayside. The reason I was looking at electric clutchs so as to give the operator a quick shut off down option in case they find that hidden rock or stump.

And also way to start the mower without having to spend mass of the bush hog blades while cranking it over.
One catch, most bush hog gear boxes aren't going to be able to handle the side load of belts running off of the input shaft, so you're going to need to make up a jackshaft of some sort that then drives the gearbox.

Aaron Z