Straight bush hog gearbox

[Bncrshr77]

Hello,
New to the forums and can't find what I'm looking for anywhere on the net..
I'm looking to turn a used pto driven 4 or 5ft bush hog into a motor driven pull behind cutter...

I'm sure the bush hog I buy will have a 90 degree gearbox on it......I'm looking for a gearbox or a way to build something so the shaft sticks straight up instead of forward.....This is so I can attach a pulley on it to line up with my 18hp B&S vertical shaft engine.

Anyone have any ideas?

 

[Soundguy]

you will need more than that. you will likely need a gearbox reducer.. something that a pto genset would use, to drop that 3600 engine rpm to 540.

I got news for you too.. you will also need a clutch mechanism or you will have a task starting it.. AND.. an 18hp whizzbang ain't gonna like a 5' mower once it hits something other than some bahia blacktop seed heads..

I think you need to go back to paper before you start buying anything..

( another option is to have the engine run a hyd pump, and use a motor control valve and a hyd motor to turn the blades... takes care of a few of your problems right there...

ps.. mke sure you leave some sort of driveline torque limiter in place.. many hace a soft bolt at the pto shaft to gearbox input shaft.. or a slip clutch at one side of the pto, depending on modle..

soundguy

 

[Bncrshr77]

I have already looked into the RPM reduction and PTO clutch.....I was assuming that if it is belt drive the belt would slip before anything tore up but will look into a torque limiter of some sort.

I don't know anything about the hydraulic side of the house but I guess I'll do some looking into it now..

I totally agree about going back to the drawing board!!!

Thanks!

 

[Soundguy]

wow.. a belt driven hog.. for a finish mower I'd do it.. but for a hog... well.. since it's only being driven by n 18hp engine.. I guess you might as well stack as much against it as you can

at least you can do some rpm matching using pulley sets... and eat some efficieny along the way as well.

good luck.. I want to see pics when it is done. Make ole rube envious!

soundguy

 

[Bncrshr77]

I've been looking into hydro setups since you mentioned them....Seem pretty interesting so far......I'm sure I will thoroughly confuse myself with it for a few days!!

One question I have is would a "two stage" hydro pump for a log splitter work for a bush hog??? There are several on e-bay that are around the GPM flow I would need and they are designed for 3600rpm engine.

 

[Soundguy]

2 stage are fast unloaded, then strong, but slower ( less gpm ) loaded. IMHO.. I would not specifically be looking for a 2 stage..

soundguy

 

[Bncrshr77]

Guess I'll go ahead and ask those of you that have the knowledge with hydraulics.....

What hydraulic size/type pump and motor would you recommend for the project I'm looking in to?

18hp Vertical shaft B&S and 4 or 5 ft Bush Hog.....I'm using the Vertical shaft because I have two of them in the barn off of mowers.

Thanks!

 

[jimmysisson]

Proper tensioned belts don't slip too much - I wouldn't count on that being the weak link. More likely is bogging down. How about using both engines, with two pulleys and belts? Enough power then, divided drive so maybe less chance of shock damage to engine shafts. And a better Rube G. photo opportunity!
Jim

 

[mwb]

Maybe you should consider removing the gearbox completely and then make a new spindle to support the blades / stump jumper. This way you can have a much simpler setup with a belt drive directly from the motor. A heavy trailer hub might do the trick. Seems a shame to spend so much on a hydraulic or mechanical work around for this. For the cost of a modified trailer spindle you might have a much cleaner design.

Can you trade someone two vertical shaft motors for one horizontal?

 

[Bncrshr77]

I've been looking into the Hydraulic set-ups and it would be lots of money to go that route.....

I like the idea of taking the gearbox off and making a new spindle. I've read that using about a 10" and 4" pulley set up will give me a good blade speed..

Looking at the DR and Swisher type pull behinds and the engine size they use I'm figuring that I should be ok with an 18 horse??

 

[J_J]

5 HP per ft, is the the general rule, and with 18 HP, you are really trying to burn up an engine.

The 44 uses a 10 HP engine, but does not sling around a heavy blade. You could perhaps modify the blades on the bush hog.

The 60 in Trail mower uses an 18 HP engine.



This hyd motor here will connect to the gear box on the bush hog, for 540 operation. but it needs 19.7 GPM's. The HP necessary to pump 19.7 GPM's, at 2500 psi, requires about 34 HP.

https://www.surpluscenter.com/item.asp?item=9-7368-100&catname=hydraulic

Swisher Products : T-44 Trailmower

Swisher Products : T-66 Trailmower

I am not saying you can't, but I would not waste a good engine.

 

[Soundguy]

get a 6' mower deck and use both engine each driving 3' of blade.. on that custom hub/spindle you are designing and even with losses.. it should cut decently in heavy stuff...


soundguy

 

[Bncrshr77]

6ft is a bit big for what I want......I figure what I will end up doing is digging around till I find a smokin deal on a 25hp or bigger engine...

Gotta figure out how I'm gonna get some kind of torque limiter/protection built into the set-up. I've been looking at an electric clutch but I don't think it will give at all..

 

[leonz]

Hello,
New to the forums and can't find what I'm looking for anywhere on the net..
I'm looking to turn a used pto driven 4 or 5ft bush hog into a motor driven pull behind cutter...

I'm sure the bush hog I buy will have a 90 degree gearbox on it......I'm looking for a gearbox or a way to build something so the shaft sticks straight up instead of forward.....This is so I can attach a pulley on it to line up with my 18hp B&S vertical shaft engine.

Anyone have any ideas?

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After going through your postings I would strongly suggest you buy a used flailmower and a one to one gear box to operate the flailmower belt drive.

You will be much better off and you will have a bit of welding to do.

I will point out that you will need to purchase a remote throttle and kill switch kit for the specific engine you wish to use and this is a must have item.

 

[SPYDERLK]

I've been looking into the Hydraulic set-ups and it would be lots of money to go that route.....

I like the idea of taking the gearbox off and making a new spindle. I've read that using about a 10" and 4" pulley set up will give me a good blade speed..

Looking at the DR and Swisher type pull behinds and the engine size they use I'm figuring that I should be ok with an 18 horse??

Blades on bushog type 5' rotary cutters spin about 750 rpm I think. 4/10 X 3600 would be way too fast.
larry

 

[Soundguy]

if you belt it it will likely slip.. otherwise incorporate a standard slip clutch.. or soft shear bolt.

(no need to reinvent the wheel ( any mor ethan you are already doing that is.. )

soundguy