Bush hog questions - The Forestry Forum

26 May.,2025

 

Bush hog questions - The Forestry Forum

I am in the market for a bush hog (rotary mower).  I think I have it narrowed down to the Bush Hog brand and Brown.  I am a bit confused by some of combinations and gear ratings.  For example, Bush Hog has a medium duty mower with a 10 ga deck and a 110 HP gear box.  Their Heavy duty only has a 90 hp gearbox, but has a 7 ga deck?   This seems odd to me.  Also, the Brown has a 7 ga deck and a 90 hp gearbox and is rated as medium duty. 

I have been told that the gearbox rating is the most important thing to consider, but it doesn't make sense that a lower gear rating would be on a heavier duty mower.  This will likely be the one and only purchase of a rotary mower for me, and I want to get one that will last.  Any explanation of the differences between gearbox ratings and quality/longevity are appreciated.  Also, any suggestions as to other things I should look for are welcome.

I intend to use the mower to clear brush and small trees ( < 2 inches)  and other general uses.  The tractor is 52 HP at the PTO.

Thanks. Your question is so technical I really am not sure how I can answer it. For starters I would think that the Medium/ Heavy Duty rating is a very subjective thing at most. I would not put too much stock in any rating such as that.

As you mention gearbox durability is the main thing. There is an incredible amount of shock load and torque placed on this major component when you hit roots, trees and dare I say...rocks? Steel thickness would also play a role in this components failure rate as well though. With thinner steel, I can only imagine the gearbox would flex and the bearings squeezed and compromised if really subjected to stress. I would also assume that more vibration would occur that would effect gear life.

If I had to buy a bush hog I would have to recommend the Bush Hog brand. Our family has owned one for more than thirty years and it has no signs of reaching retirement. I doubt anything today is made as good as it was thirty years ago, but Bush Hog has a strong reputation nonetheless.

Perhaps one of the reasons it has lasted so long though, is that we do not use a gear lube in the gearbox. That seal failed years ago so for the past few years we have used a Crater Compound type grease used in locomotive gearboxes. I have no idea where a non-railroader would obtain such stuff, but the grease is designed for such stress, is thick so seals are optional, and so tacky that WD-40 is the only thing I know of that takes it off.

I am not so sure how much all of this will help you in your new purchase, but I wish you all the best of luck.

Here is a link to some pictures I took while Bush Hogging our tree plantation a few years ago for whatever it is worth...

http://www.railroadmachinist.com/WDL_Trees.html

All the brands mentioned are great in a single spindle cutter.  Another is Bushwhacker.  They only make HD cutters (4 inch cap.)... 

Check the weight of the stumpjumper.  The more weight, the more interia you have. 

Somthing else to consider is the driveline safety system.  Some use a slip clutch and some use a shear bolt.  Shear bolts are nice and simple till you run out of bolts for the day.  :   Slip clutches instantly recover but require some maintence and periodic adjustment. 

Buy or make safety chains for both ends of the deck.  I found an old basket ball in a fencerow today and the cutter threw it 60-70 feet.  Put several fist sized holes in it.  Had it been a heavy object there's no telling what damage it would do. 

Woods gearboxes seem to be weak in batwings but that's another thread. 


Anyone want a slightly used basket ball?   :D


You bring up one of my favorite subjects Boardmaker on any topic...safety.

Another problem you mentioned about the driveline protection system of sheer bolts is that after a few sheer pins break, they shove in a grade 8 bolt. Sure beats buying a ton of those grade 2 bolts you get at the Box Stores, but then when you hit something real hard, well if the bolt doesn't break, something has to give!

Another thing is having passengers aboard. I know as a kid I spent days riding on my father's tractor while bushogging, but that was another time and another place. A few years ago a 2 year old child fell off a tractor and was run over while his father was bushogging right here in town. The child did not live. Just the other day I was watching a show on TV that depicted an older farmer who was also run over while bushogging. While that man lived, the point of the whole story was that he should not have.

I do not want to nag, but let's not get complacent with the implements either huh? I would rather make a post such as this, then to make a post saying member so and so was recently maimed or killed while bushogging. It seems to me that most manufacturers rate their mowers more by the thickness of the steel than just the gear box.  That is if your cutting 4" saplings with a mower rated heavy duty you need a good thick deck or it will never hold-up.  A medium duty for 2" saplings doesn't need quite the deck thickness or reinforcement.  If you look at most gear boxes and compare the usage rating , not just the hp, there is usually a physical difference in size and design for light vs. heavy. 

Deadwood I know what you mean about the seals.  Back in the '60s my uncle bought a John Deer tractor and a mower.  The seal was bad from the begging and ,after a few attempts to fix it, John Deer replace the oil with greese.  It was still the same grease when I got the mower in the early '90s.  The only advice my uncle gave me was if the tractor can ride it down the mower can cut it. :D brdmkr.    You say brush and small trees  2" ??    How many acres a year are you doing ? Any outside work etc.
I have gone thru three  JD's in 20 years..   Lots clearing, pasture and field rehab. 
" Slip clutch is a must have."  I have no mercy on my brush mowers,they are purchased nowing i will be relacing it in a few years..    Mower #1  5" purchased 2 MO's used  lasted 8 years " rock threw deck driver shaft snapped.  Mower #2 JD 615 purchsed new  lasted 7 years  strattled large rock  tractor dropped into rut  what a sound !!!  checked things out all looked fine mowed for anothe hour and then BANG  Power box got the runs drive shaft snapped parts every where.  Went to dealer got # 3 an MX 5 Med duty made it threw this spring and then  doing some pasture rehab for a neighbor farm, the mower came down w/ Hardware disease!! She sucked up a chunk of steel in the pasture and that was it !!!  spit the blade deck out landed 50' away no noise or anything " Made an errie POOF sound" when it stopped.......
  The farm I worked on as a kid had a Bush Hog bought brand new lasted a good 20 + years and then the deck rotted out,,, Maitainance is a must clean down the deck and oil for winter storage....   Grease,Grease, Grease.....

I really don't think these machines are ment for trees and 2 inch clump brush need a backhoe or loader... Brontasarus brush grinder might be the answer.......   Although my machines have paid for them selves and made me quite a bit of money. mower  #1 cost $525. = $75 per year income per year $.00  mower #2 cost $ = $185 per year  mower # 3 cost = $ 375 per year.  cleared $  from the last pasture rehab before the mower retired...   Will be getting a new on in the spring  !!   going extra heavy duty .....
Quote from: crtreedude on October 31, , 05:18:02 AM
Has anyone had any experience with the Bushhog that goes behind an ATV? We have a lot of land that we keep clean, I was wondering if it might work well. We have a spacing between trees of 3.5 meters so it should pass with no problem.



They work reasonably well but are much lighter than the three point mounts. There is no pto on the atv so they have a long arm out the back with the engine hanging off it. PITA to hook up and remove too. Fine for the acreage owner or hobby farmer but  too pricey and not for serious work. As others have mentioned, the "heavy" and "medium" dutly rating are very subjective.  Metal guage and gearbox HP ratings are the best objective measures you will find.  For cutting grass and other soft vegetation, a lighter duty mower is fine, but if you want to cut brush and saplings, get the most heavy duty mower you can afford, but be sure your tractor can still lift it.

For the use you describe, the deck metal guage matters just as much as the gearbox, in my experience.  I woudl also highly recommend a slip clutch.  Cutting woody material pounds the hell out of the mower, and the deck will develop cracks if it is too light.  I've used a Woods 4' "medium" duty mower for many years now in some very abusive conditions, and last year I had to weld up all the cracks, pound the grearbox mount back into alignment, and rebuild the gearbox.  For a variety of weight/terrain reasons, I can't use a heavier mower, but would if I could. We had 2 BMB bushhogs when I was growing up.  The first one was a 6' wide one and just died 2 years ago because the gearbox gave out.  The other one was the biggest 3pt one thatwe could get- it had 2 blades on it.  The gearboxes gave out on it too- but only one of them- so it chewed up the blades pretty quick.
Right down the road from here is the Rhino plant.  They are the previous manufacturer of the BMB brand.  They have done a lot to improve their driveline.  Whenever I get a tractor for my place, I will be getting a Rhino.

Just my 2 cents

Charles We have a heavy duty Bush Hog brand 5 ft pull type that has torn up two tractors and put a lot of wear on three or four others in the past 35 years.  We've put a lot of blades on it and replaced a few bearings and hundreds of shear pins,  but nothing major.  It's still doing a good job.

We also have a 10' sidewinder that we bought about 10 years ago.  We cover a lot of acres with it,  but not as rough of cutting as the Bush Hog has done.  It has a slip clutch which has caused no problems,  but the metal sides are about gone,  I've spent hours welding on it,  had to replace the stump jumpers.  The gearboxes have held up,  but had to replace one of them right off because the shaft that holds one of the  three blades broke.  The warrenty covered it,  but won't the one I broke last week.  I think the machine is ok,  we just have too rough of ground for a wide fixed cutter.

One type of driveline protection that I don't believe has been mentioned is the friction drive that the smaller 'sidewinders' use.  I wouldn't mind having one of those on a 3 pt.  People who use them seem to like them.

Rotary Cutter gear box ? | OrangeTractorTalks - Everything Kubota

tater pop

Member
Jan 13,
64
0
6
Maud texas usa
  • #1
I'm in line to get a new cutter. I have a mx- tractor I will be mostly cutting grass some a little hard to cut(watergrass) . looking at getting a 6FT rotary cutter . Does the higher HP mean slower RPMs I will not be clearing land with it.I just need something thats makes a clean cut.

gpreuss

New member

Equipment LDT w/FEL, K650 Backhoe, 5' Rotary, 40" Howard Rotavator, 6' Rhino blade
Oct 9,
1,166
6
0
Spokane, WA
  • #2
Mostly the higher horsepower comes from more torque, although with the MX you have to run rpm to get 540 at the PTO. The mowers are all made for 540 rpm, and cut best at that speed. If you slow them down too much you no longer get a clean cut.

TripleR

Active member

Equipment BX, BX, L HSTC, MHDC and some other tractors and equipment
Sep 16,
1,911
8
38
SE Missouri
  • #3
Not necessarily, check the Land Pride web site and it will give you blade tip speeds etc. and some high HP mowers are essentially the same as lower HP models. I haven't check other makes, but don't know why they would be different.

I use an RCR and it works well in grass as well as brush. Lots of definitions of water grass, so I'm not sure what you have.

Bulldog

Well-known member

Equipment M DTC, L DT
Mar 30,
5,434
76
48
Rocky Face, Georgia
  • #4
Like TripleR said, the blade tip speed is what you need to look at. For example, my Bushhog is 16,345 fpm and it has a very high quality cut. If you want a good cut for grass I wouldn't even look at anything under 15K fpm.

tater pop

Member
Jan 13,
64
0
6
Maud texas usa
  • #5
Thanks for your answers, the reason I ask the question is years ago I had an older bushHog brand bush hog with the old big gearbox that thing would clear a thicket but did not make a good cut on pasture grass. My neighbor had a ford cutter with a small gearbox that would make a better cut in grass at a faster speed than I could run .

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