Brush Cutter Size

[logan97]

looking into purchasing a Bush Hog for a Kubota B7800 30 HP, need to cut over grown briar's and saplings up to 1" to 2" in size, and grass. Will 5' be to large ?
P.S. would a tooth bar help with removing the briar's

 

[leonz]

Your topic has been covered extensively on
the "Attachments Section" over several hundred pages.


What you have understand/must understand completely
is the mechanics of any, I repeat any rotary cutter;


Only half of the cutting surface length is being used at any time
when you are trying to knock down brush or grass the other thirty
inches is unused at any time where witha 5 foot flail mower
the entire 5 foot width is being used to slice the brush in front
of it.


As you have a varied brush load I would strongly suggest
you chat with Ken Sweet who is a sponsor of the forum in
good standing first as he is a sponsor of Tractorbynet.com.
regarding a 48 inch flailmower with hardened knives for your
use.


You also have to under stand the rotary cutter will leave
massive amounts of debris that will remain and not degrade
or mulch quickly.


If you do a search on flail mowers here in the forum you will
find a lot of happy owners of flailmowers also, but please give
Ken Sweet a call first about a 48 inch flailmower for your needs as
a 5 foot rotary cutter is really too large for your use even with
mixed use mowing.



About the briars a small box blade with the teeth set deep will
be better after the briars have been knocked down.



leonz

 

[LD1]

Flail mowers are more $$$. Used bushhogs are a dime a dozen. No doubt a flail mower is the way to go if money were no object. But since you asked about rotart cutters, I'll give you my opinion on them.

I think you would be better suited with a heavier duty 4' cutter. You have the HP to run a 5'er effectively, but the size and weight become an issue vs your smaller framed tractor.

I have a tractor that is ~800lbs heavier than a B7800, and I definatally can tell there is a 5' cutter back their. With a smaller tractor, it is like the tail wagging the dog. That much weight that far back puts a lot more stress on things. And side loads when turning. Not to mention going up even a small hill. I perfer to "hog" without the FEL for added manuveribility, but if I were any lighter, hills would be a challange.

So, IMO, you would have a better time with a 4' cutter.

 

[gerard]

You're rated for up to a 6 footer. My L2500 is a little smaller, I use a 5 footer and COULD use a 6. You at least want to cover your tire width so I would NOT go with a 4 footer. You can always adjust to conditions by going slower and/or raising the cutting height but if you have light cutting, you'll never cut more than 4 feet in a pass with a 4 foot mower! If yuou have an hst it's even less of an issue since you can just go at the max speed that allows the rpms to stay up there.

 

[Will_C]

5 foot would be a fine match for a B7800. I would watch the weight, some of the extremely heavy duty models might be more weight than your tractor can handle without the "tail wagging the dog" so to speak.

Will

 

[leonz]

I was not going to bring price into this posting
as I was determined to explain only the differences
between the two types of mowers:

As you are this close to an Agrisupply show room
you can pick up a new 4 foot Caroni flail for a few
dollars under $1,500.00 U.S.D., plus tax at the
showroom in Petersburg Va.

 

[Marveltone]

Another option people seem to forget about is the Woods 54" RC. It's offered as an alternative for people with smaller tractors. I use it with my Ford 1510 and love it. Your tractor makes more power than mine, but it's also much lighter, and as others have pointed out (tail wagging the dog), that can be some cause for concern.

A common problem nowadays, IMHO, is the tendency for manufacturers to put more power in smaller packages, which can make for a compact powerhouse, but makes actually using and handling implements near the outer limits of the machine's capability an increasingly dangerous practice. For instance, your Kubota makes 30hp (22PTO)and can power and lift more at the 3-pt hitch (1655 lbs vs. 1432 lbs) than my Ford @22hp (19.2PTO), but can it handle it? (Tractor weight= 1740 lbs vs. 3200lbs) Rotary cutters leave a lot of mass hanging several feet out the back of your rig. Tractor weight is your friend.

Sorry if I muddied the waters. :ashamed:

Joe

 

[logan97]

Will the FEL Bucket or Forks to put counter weight , help the wag ?

 

[LD1]

It wont really help the "wag" but it will help offset the weight when going uphill.

But as mentioned, I personally dont like the FEL on. The tractor visibility and manuverability are much better without it.

 

[belah]

I don't know what type rotary cutter you are considering but I just purchased a Wood's BB 720 6ft cutter. I have a larger tractor so the 1100# weight is not a problem. Wood's makes a BB72 which weighs only 800# for the 6ft model and even less for the 5ft model- 600#. It is rated to cut 2 in saplings. I love the Wood's cutter because it is the only cutter on the market that allows you to change blades from the TOP(no more crawling under the cutter) and it also has the longest gearbox warranty of 6 yrs. You can go to their website Wood's Equipment and compare the wood's to about 5 other brands of cutters side by side.:thumbsup:

 

[new jersey mike]

I was debating the same decision last year. I "had" heavily over grown fields. I decided on a new 45hp tractor and a 6ft rotary from Bush hog. I decided to also buy new this way any abuse was from me. The mower is limited with the diameter it cut and I will come back with a chain saw and than brush hog the remainder in the real heavy areas.

I don't agree with comment of the front part of the mower is only being used. When a sapling is cut is it not chopped more before coming out the back? And if you were to have the back edge 1 inch lower then the front it would mulch more material but is more strenuous on the tractor.

I have leaned a lot from reading here and really appreciate it. So what do I know, the hp of the tractor, the height and age of material maters, the speed that you move forward matters, the height of the deck and angle of the deck matters, is the field level? Cut moving downhill to ease the load. You don't have to cut a full 6ft swipe either. The dealer told me I did not have to have to run high rpms and I guess he never thought this "green horn" would not do what I did. I am sure many will also say RPM's matter it's what is turning the bade and moving the tractor. If you have a bucket keep it low so you push down the material you cut.

And if your unsure go around it.

I hope this helps.

 

[leonz]

The leading edge of the rotary cutter is the ONLY cutting surface
that is meeting the brush that is entering the mower housing the
same rule applies to a belly mower.

The leading edge becomes the following cutting edge at each rotation
and simply flies over the material that hacked up by the leading edge
its nothing more thana merry go round of brush mower blades.


The brush is left to rot and takes forever to rot down to dust and you
have a lot of dead spots that will provide food for the bad bugs in the soil.

if you want to beat the living daylights out of the ground and the brush mess
that will sit on the surface you- lower the rotary cutter all the way down and
allow the mower to slide on the ground using the side walls of the mower deck.


After the brush is cut you will have no ability to recut the material and shred it further -
unless and until it is so dry it is brittle and what little sucton is occuring ccan lift up the material.

 

[Sackett2]

i bought A 4" hog when I got my tractor, and was chastised about it not covering the wheels. That 4' hog has done very well, and i love it with brush and saplings. the smaller diameter doesn't bog down in the heavy stuff as a larger one would.
I am buying a near 6' Chinese one from Betst for this year. This will be used on the big field jobs where time is important and I'm not into big bushes all the time.

 

[gerard]

My 3 pt capacity is 900lbs, have a med duty bush hog that weighs 600lbs. Wouldn't even consider going smaller than 5 foot though 6 COULD be a problem based on ability of 3 pt to lift. (Once you go to 6 foot they tend to be either med or heavy duty and I might be crowding the 900 lb capacity of my 3 pt).

Not sure I agree totally with the front edge doing the only cutting. There is a mulching action when cutting 3 foot high grass and that grass gets chopped up the longer it stays churning around under the deck. Lowering the back as opposed to the front keeps the cuttings in the deck longer and chops them up more. Also takes more power to do so. Tilting the deck so the front is lower than the rear allows the spoils to exit quicker and get chopped up less, easing the load on the tractor but not chopping up the grass/weeds as finely. There is no real "right" "wrong" way. Depends what you want to accomplish. One thing you DO want to do is keep the top link slack so it floats freely. That's how the mower keeps somewhat level when going over mounds and hills. If you keep it taught (no play in the linkage), the mower will rise and fall as the wheels go up and down which will give you a bit of a choppy cut. Not an issue if you have perfectly flat fields.

 

[LD1]

I guess I am kinda the odd man out here. But again, my tractor is a little bigger and a little heavier and I use a med. duty 5' cutter. I can personally say I would not want to run it on a smaller/lighter tractor with 7HP less at the PTO. But again, this is just one guys opinion.

I do like whoever mentioned the 54" cutter. I think that would be a good fit for you.

And I also dont really buy into covering the wheel tracks. At least not for bushhogging. I see no advantage to it. But going bigger, you have to be careful when mowing next to things. With the BH being wider, it is easy to catch it on things.

And in your given HP range, you can mow with a 48" or 54" just as fast as a 60" ore even a 72". HP will determine how fast you can cut. NOT BH size. You will be able to mow faster with the smaller cutter, but take a smaller swath. But in the end, acres per hour are determine by HP.

 

[Verticaltrx]

I use my tractor commercially with a 5' bush hog, so I have plenty hours running this setup. 5' is just fine so long as 1) the unit is not too heavy and 2)the back of the bush hog isn't too enclosed. I use a Kodiak 5' that I got from Agri-supply and it was the right combination of durability and light weight. I also like the Woods Brush Bull and some of the offerings from Hardee, but they were too heavy. The one I have is also more open at the back than some other cutters, and therefore takes less power to run (discharges the cut material easier). We had a 5' Deere bush hog that was completely enclosed at the back and it took an amazing amount of power to run (at least 35-40 PTO hp in anything heavy).

I use mine with both the loader on or off and don't have any 'tail wagging the dog' syndrome. With the loader off a few suitcase weights on the front would help steering, but isn't necessary.

 

[Soundguy]

2" woody is too big.. green maybee. though I like to limit diet on that size of machine to 1.5"

you have the hp for up to 6'

soundguy

 

[gerard]

I guess I am kinda the odd man out here. But again, my tractor is a little bigger and a little heavier and I use a med. duty 5' cutter. I can personally say I would not want to run it on a smaller/lighter tractor with 7HP less at the PTO. But again, this is just one guys opinion.

I do like whoever mentioned the 54" cutter. I think that would be a good fit for you.

And I also dont really buy into covering the wheel tracks. At least not for bushhogging. I see no advantage to it. But going bigger, you have to be careful when mowing next to things. With the BH being wider, it is easy to catch it on things.

And in your given HP range, you can mow with a 48" or 54" just as fast as a 60" ore even a 72". HP will determine how fast you can cut. NOT BH size. You will be able to mow faster with the smaller cutter, but take a smaller swath. But in the end, acres per hour are determine by HP.

I understand what you're saying about hp being the limiting factor and theoretically that's true but that assumes you can drive at a speed as fast as your mower can still cut the grass/brush with the available hp. That's not really true in bumpy ground. When cutting light weeds/grass in my pastures, my limiting factor turns out to be how much I'm willing to bounce around so I may have excess hp and I still can't go/cut any faster. Hence I can cut more acres/hour with a 5 footer than I could with a 4 footer because I just don't want to drive any faster. Just a case where real life doesn't always meet theory. (I've also been told a 7 foot back balde is too big for my tractor. Guess I still haven't learned that after using it for 10 years and not wanting anything smaller)

 

[Jerry/MT]

looking into purchasing a Bush Hog for a Kubota B7800 30 HP, need to cut over grown briar's and saplings up to 1" to 2" in size, and grass. Will 5' be to large ?
P.S. would a tooth bar help with removing the briar's

The rule of thumb I use for rotary brush cutter sizing is 5 pto hp per foot of cutter. It's conservative and accounts for mowing up hill, etc and tall heavy grass and if it comes out to 5.5ft that you can go to the nearest higher foot. it's also good to have the cutter at least as wide as the rear wheel width.

Watch out for the weight of the mower because when you lift the mower your steering gets lighter.You don't want the front wheels coming off the ground. I have a 6 ft mower that weights 750 lbs on my old TO-30 ferguson and while the hydraulics will lift the mower, the sterring is marginal with the mower off the ground. Fortunately youmow with the mower on the ground!

 

[Soundguy]

I guess I am kinda the odd man out here. But again, my tractor is a little bigger and a little heavier and I use a med. duty 5' cutter. I can personally say I would not want to run it on a smaller/lighter tractor with 7HP less at the PTO. But again, this is just one guys opinion.

.

it's a ground speed vs hp vs weight issue.

if you have enough weight to safely tote a 6' but hp is a lil lower than optimal.. then use a lower ground speed.

I use a 5' hog on a weak lil ford 8n.. it's not optimal at high speed.. but in 1st gear and max throttle I've mowed 7' tall weeds

soundguy