Rotary Cutter Rotary Cutter Advise

[moonmark1980]

I have a Kubota L4850 which has 42 pto horse and I'm looking for some rotary cutter advise. I've decided a 6' cutter is what I want, but my questing is. Will a Bush Hog BH26 cut bigger brush than a Bush Hog BH16 when your operating with the same pto horse? Will a Land Pride RCR2672 cut more brush than a RCR1872 or a RCF2072 with the same pto horse? I know the larger cutter has more capacity, but does it require the the maximum horse power to have the additional cutting capacity?

 

[brown40]

Yes, you need the extra power to shred larger brush. Technically, any 6 footer has the same potential to do work (cover the area), but the attachment is built to the use varies by the customer.
A light duty machine with a light gearbox and driveline is more easily turned, and usually has higher blade tip speed for a cleaner cut on light brush with few challenges. A heavy duty machine is harder to start and stop, tends to have a lower blade tip speed, and has a very robust gearbox and driveline to address overgrown areas and reclamation.
You'll waste money buying and spinning a heavy cutter on light duty work... you'll rattle apart your light duty cutter on any amount of heavy duty work.
The ratings of 1, 2, 3, 4 inch cutting capacity and relative weights and ratings of the units are there to help you figure out which series matches your use.
You pto power translates into the maximum "bite" your tractor can take--the heavier the unit, the more mass and inertia are presented on impact, the more likely you'll shatter the brush. You meter how much oomph any shredder delivers with the shear pin/slip clutch, so ideally you never have your engine drag, lug, or stall. Lighter units don't hit as hard and will drag on your engine more to get through the same brush.

 

[mcfarmall]

Here's another thought. Many cutters will state "Capacity: 3" diameter" or whatever. Because the blade is enclosed under the deck, you must get the 3" diameter material under the deck where the blade is spinning. Do you think this means the cutter can hack up a piece of tree trunk or a branch 3 inches in diameter just laying on the ground? Or does this mean the cutter has a frame, hitch and deck strong enough for you to plow over a 3" sapling, bend it over, shear it off at ground level and shred it into small pieces?

Think of the process this way: You are backing the cutter into a mess of brush and saplings one of which is 3" in diameter. The top edge of the rotary cutter is 10" off the ground. Imagine the amount of force you'd have to apply to a tree this size 10" off the dirt to get it to bend over sufficiently to get it into the cut zone. First off your tractor has to have the guts to apply the proper amount of force, the cutter has to be heavy enough to not just rise up the trunk and skin off some bark, and the blades and blade carrier have to have enough momentum or inertia (stored up energy) to hack the tree off and shred the remains.

I run a 5' King Kutter that is about 30 years old with the Farmall C and can safely and easily attack 1 1/2"-2" saplings, oak, sassafras, wild honeysuckle. Anything bigger when I back over it, the cutter rides up the trunk and more or less pops it partially out of the ground. I can drive over them forwards as well due to the 24" ground clearance and the fact that the massive rear axle housing will bend them over sufficiently so they will glide under the front edge of the cutter and be shredded.

Bottom line is get something with enough beef so your tractor won't tear it up when attacking large brush.

 

[Piston]

The biggest difference you'll see 'power' wise, is that the medium duty cutters like the BH26 and RCR2672, will take more of your PTO power to GET them turning. Once the blades are spinning, it won't make such a difference regarding needing more PTO power to run the medium duty over the light duty. There isn't a direct relationship between power required on the heavier cutter though. The heavier cutters have more mass in their blades, which translates to more force and momentum when hitting something large, so although a lighter blade will spin easier, it will also slow down easier when hitting something, where the heavier blade will want to continue spinning and use momentum to shatter through a sapling.

Power wise, you will have no problem at all with the medium duty cutter. The biggest difference you'll see is that the medium duty cutters will actually last, and not bend and crumple when getting into heavy brush. I had a light duty cutter and very quickly bent and mangled it very easy with my mere 39PTP hp. I upgraded to a medium duty Brown 472 cutter, similar to the other medium duty ones you are looking at, and although not bullet proof, they will easily take down heavier brush all day long.

I don't use my rotary mower at all for nice field mowing, it's all heavy brush and field reclamation work. As mentioned, the light duty mowers will not stand up to that.







With 42PTO HP you will easily operate either of the mowers you asked about.

 

[ArlyA]

Pisten, What you show is largely what we'll need to mow. This is why we're looking at med duty mowers as well and we know that we'll be striking the unseen stumps, rocks and dirt with it.

 

[LD1]

No difference while cutting.

The difference is the durability of the cutters. Get a cutter rated for 3" material and use it on nothing over 2" material and it will last a lifetime.

Get a cutter rated for 1.5" material and try cutting the same 2" stuff, you will have the cutter destroyed before long. They are built lighter. Lighter deck and framing, lighter gearboxes with smaller bearings and shafts, etc. Sooner or later, something will break.

Not everyone needs a heavy cutter. Alot of people just want pasture maintenance (just weeds and grasses) a few times a year. No point in spending the money on a real heavy cutter thats rated for 3" trees.

ANd if you are gonna cut alot of grasses, pay attention to blade tip speed. On 6" cutters this can vary widely. Some as low as 10.5k fpm others well over 16k. Just like a lawn mower, faster blade speeds leave a nicer cut on pasture grasses.

 

[moonmark1980]

Thanks everyone for the advise, I believe I have my answer. Which is what I though all along, but the 3 implement dealers I talked to yesterday all tried talking me into a lighter duty cutter. They said that if I wasn't in the higher pto power range on the medium duty cutters I would not benefit from the medium duty cutter. They said the the BH16 and RCF2072 cutters were build heavy enough for the tractor pto horse I had. So I got to second guessing myself and thought I'd ask. 95% of my cutting will be food plot and trail clearing in heavy bush on a 40 acre strip pit/mine that hasn't been touched in 40 years. I've been working at it the last 2 or 3 years with my old Massey 135 with a 5' Howse cutter and I've about cut all it will cut and decided it was time to move on to something a little bigger.

 

[nybirdman]

I have a similar tractor(L4240 Kubota)and a six ft.Landpride RCF 2072,I would not run over 3-4" trees to cut with my machine.You can't back into them either,it will just lift the cutter.Unless you amour up your under-carriage you are asking for damage.Cutter has been good(broke one blade on a rock),make sure your slip clutch is serviced every year.

 

[LD1]

PTO hp isnt what destroys a lighter cutter. And isnt what chops up the occasional heavy piece of brush. Inertia does that.

It dont matter weather you have 20HP at the PTO or 200HP at the PTO. When you hit an unseen downed tree ~4", or a unseen rock, stump, etc. Again, its all inertia not HP that will do damage to the cutter. The heavier cutters arent gonna tear them selves apart. So yea, clearing dense brush and blazing trails....you absolutely will benefit from a heavier cutter.

IF you were just clipping pasture grasses that get done yearly or multiple times a year, I'd be inclined to side with the dealers that say you wouldnt benefit. But it sounds like they dont have a good understanding of what you are wanting to do.

 

[ovrszd]

No difference while cutting.

The difference is the durability of the cutters. Get a cutter rated for 3" material and use it on nothing over 2" material and it will last a lifetime.

Get a cutter rated for 1.5" material and try cutting the same 2" stuff, you will have the cutter destroyed before long. They are built lighter. Lighter deck and framing, lighter gearboxes with smaller bearings and shafts, etc. Sooner or later, something will break.

Not everyone needs a heavy cutter. Alot of people just want pasture maintenance (just weeds and grasses) a few times a year. No point in spending the money on a real heavy cutter thats rated for 3" trees.

ANd if you are gonna cut alot of grasses, pay attention to blade tip speed. On 6" cutters this can vary widely. Some as low as 10.5k fpm others well over 16k. Just like a lawn mower, faster blade speeds leave a nicer cut on pasture grasses.

I was scrolling down to add these comments.

Good stuff right here.

Worry less about HP requirements on light versus heavy cutter. Worry more about the durability and life of these cutters.