Why Can't Someone Make a Good 12' Batwing Cutter?

[Brown Dog]

You Shoulda bought a M series JD

 

[John H.]

I have been looking for a high quality 12' batwing cutter for a long time now...

They make great 15 foot cutters, but when you want a 12' for tighter areas and less horsepower, the lineup of what's out there is just disgusting.

Currently I have a Modern Ag 12' Viper. I have a love/hate relationship with it. It is used for light duty only, mostly just mowing weeded pastures without any or sparse, small brush. It gets pulled behind my 75hp Powerstar.

The Viper leaves a nice cut, and I love the galvanized deck, but other things leave me puzzled, such as the very light duty wing leveling turnbuckles, and having the wing gear boxes sling all the gear oil out through the vent nut on a daily basis. I mean I have to add lubricant nearly on a daily basis. Vibration on the cutter has always been very rough. You'd better check those gear box bolts and re-tighten them to the deck often. Drive shafts have to be disconnected, cleaned and greased by hand very often. No grease fittings that lube the shafts...

The Woods BW12 is by far the worst cutter I ever used. Once it gets a bit of use and gets dirty, the wings won't go up or down due to the extremely tight wing hinge pin, and no way to lube it. When you can't use the wings, it kinda does away with the need for a batwing, right? Sold that cutter for half of what I paid for it, just to be rid of it.

Several manufacturers make very good 15' batwing cutters.

Why is it so hard to make a decent 12'? Seems like all they would have to do is scale a 15' cutter that has been time tested and proven and last decades, and scale that down to be a 12' cutter?

If any of you have any input as to better quality cutters in the 12' wide size, I'd love to hear of it!

Just posted on another thread. I have had multiple issues with gearboxes (two replaced under warranty), gearbox seals (both ends of the gearbox), a seal on the breakbox, and just yesterday another gearbox seal and a blown hydraulic seal on the wing lift. This thing is lightly used, meticulously maintained, and kept in a barn. Dealer has been excellent in assisting with these issues, but based upon mechanic comments, I don't think my problems are unusual. Thoughts? Am I missing something I should be doing? I certainly would not recommend this shredder under any circumstances.

 

[John H.]

Just posted on another thread. I have had multiple issues with gearboxes (two replaced under warranty), gearbox seals (both ends of the gearbox), a seal on the breakbox, and just yesterday another gearbox seal and a blown hydraulic seal on the wing lift. This thing is lightly used, meticulously maintained, and kept in a barn. Dealer has been excellent in assisting with these issues, but based upon mechanic comments, I don't think my problems are unusual. Thoughts? Am I missing something I should be doing? I certainly would not recommend this shredder under any circumstances.

Shredder is the Modern Ag Products 12 foot Viper batwing.

 

[rockinbbar]

Just posted on another thread. I have had multiple issues with gearboxes (two replaced under warranty), gearbox seals (both ends of the gearbox), a seal on the breakbox, and just yesterday another gearbox seal and a blown hydraulic seal on the wing lift. This thing is lightly used, meticulously maintained, and kept in a barn. Dealer has been excellent in assisting with these issues, but based upon mechanic comments, I don't think my problems are unusual. Thoughts? Am I missing something I should be doing? I certainly would not recommend this shredder under any circumstances.

John, yessir... You have the same issue I do.

I've gone to using 00wt Cornhead Grease in the gear boxes of the Viper now. It throws much less gear oil out on the deck, and stays inside the gearbox rather than leak through seals.

I've had both wing hydraulic cylinders replaced twice. Now I have noticed blow by of hydraulic oil in the deck level cylinder. When I hooked it up and raised and lowered the deck, the oil shot out of the vent nut in the deck cylinder and blew all over the back of my tractor cab. Nice touch... LOL. (I twisted that vent nut to face a different direction now)

On the bright side, I replaced my 11 year old Woods 15ft HD cutter with a new Woods 15.72...

Man! THAT is the ultimate cutter! Now if I can only talk Woods into incorporating that design on a 12 ft cutter.

That 15.72 is by far the best and smoothest cutter I've ever run!

 

[RayIN]

I don't think you can get much better quality than a Schulte FX-212.

I like the specs!

 

[John H.]

Well, I put about 75 to 100 hours a year on the Viper mowing pasture. I have never gone more than two years without a major problem and a trip to the dealer. The mower is about six and a half years old, and problems began at about 30 hours when the center gearbox failed. Seals are a major recurring problem. I have a lot of John Deere equipment, including an MX6 that is 25 years old with never an issue. I made a serious and expensive mistake in purchasing the Modern Ag Viper. I’ll be off to the dealer again next week and probably out another grand plus.

 

[dadohead]

Another thing I look at in the specs is the blade tip speed. The higher, the better.

Retired mower engineer here... to your point: absolutely not.

Impact cutting starts at about 11000fpm. Below that, it "combs" the material. As you spin faster however, the power requirement to run the mower goes up exponentially. ANSI standards limit the upper end of finish mowers at 19000fpm for safety reasons (thrown objects, broken blades, noise, etc).

High tip speeds can make sense for a commercial finish mower designed to cut  well at 6 mph. They also require +30hp to operate!

Belly mowers and rear cutters have to deal with the tire tracks from the tractor. They will never cut like a front mount mower regardless of tip speed... better to slow them down so they have good  power to get through the tough stuff.

Something to consider: blade pass frequency. Manufacturers don't publish this; you must calculate it. Example: a typical 6' single spindle rotary cutter runs around 15000fpm. Cutting at 3mph, it makes a cut (blade pass) every 2" of forward travel. A 6' TWO SPINDLE cutter (two 3' blades) must spin faster to get to 13000fpm but the blade pass is 1 cut/1" traveled. Slower tip speed (less power) but double the cuts/inch travelled!!! Tip speed is NOT the whole story!

 

[hayden]

You guys have me worried. I bought a LandPride RC2512 last fall at a great end of season price. I rationalized a lighter grade mower because I’ll only be cutting grass. Anything heavier I’ll use my Woods BB720 which has been indestructible.

One thing I plan to do is pill the pivot rod and separate the wings, and drill
And tap for grease fitting.

Fingers crossed that it does what I need.

 

[rockinbbar]

Retired mower engineer here... to your point: absolutely not.

Impact cutting starts at about 11000fpm. Below that, it "combs" the material. As you spin faster however, the power requirement to run the mower goes up exponentially. ANSI standards limit the upper end of finish mowers at 19000fpm for safety reasons (thrown objects, broken blades, noise, etc).

High tip speeds can make sense for a commercial finish mower designed to cut  well at 6 mph. They also require +30hp to operate!

Belly mowers and rear cutters have to deal with the tire tracks from the tractor. They will never cut like a front mount mower regardless of tip speed... better to slow them down so they have good  power to get through the tough stuff.

Something to consider: blade pass frequency. Manufacturers don't publish this; you must calculate it. Example: a typical 6' single spindle rotary cutter runs around 15000fpm. Cutting at 3mph, it makes a cut (blade pass) every 2" of forward travel. A 6' TWO SPINDLE cutter (two 3' blades) must spin faster to get to 13000fpm but the blade pass is 1 cut/1" traveled. Slower tip speed (less power) but double the cuts/inch travelled!!! Tip speed is NOT the whole story!

Interesting occupation! What company did you retire from?

I absolutely don't agree with you that blade tip speed doesn't make a difference, though. (We are talking rotary cutters here, and mowing acreage with brush, weeds, and uneven terrain. Not finish mowers, as I would have a finish mower last nearly as long as it takes the water to get hot.

Even using your simple sample of math, a higher blade tip speed, combined with not mowing too fast would result in a cleaner cut, due to the distance traveled before the blade swings around and cuts. Right? But aside from "grass" I shred ranches with sometimes heavy growth of mesquite and huisache brush, along with other hardwood brush varieties.

When shredding ranches with 3-5 foot of brush growth, a higher blade tip speed means that I get a cleaner cut, and have to circle back less often to cut down the stragglers.

On my Heavy Duty 15' cutter, it is blade tip speed rated at 15,526 (wing), 16,286 (center) at 540 rpm.

As to the extra horsepower on a finish mower, I couldn't tell you because I don't run those, but I do know that using a batwing cutter through heavy growth can slow your rpm's down because the cutter is just simply cutting more than it can handle when you go through it. If you have enough horsepower to power through those thick areas, cutter and blade tip speed is maintained, and you get a better cut than being under powered with horsepower on the tractor, and having rpm's drop in both PTO speed, and blade tip speed.

When running a batwing cutter, if the design has opposing spin directions on each wing, it will give a cleaner cut than a cutter geared to only spin one direction on all cutting platforms.

I'm glad you saw this and offered input and engineering experience! But, I can't help but think that finish mowers and heavy duty batwing cutters rated to cut 4 1/2" brush may be two very different things.

Sometimes, I use that big guy to do some finish mowing type work though. And can't fault the end result.

 

[dadohead]

I retired from John Deere... put many tractors and mowers into production over the years. It's ok to disagree. ;<)

I'm not saying tip speed doesn't make a difference. I'm saying it's not the whole story and "faster is not always better".... you pay a big price in power concumption to swing the blades fast and often the cut is not improved.... especially if you bog in tough cutting (finish or rotary cutters).

I little secret: spindle placement is HUGE. Tire tracks from the power unit push the grass forward and mash it down. If mid mount and rear mowers designers had their way... they'd place the 'back sweep' side of the mower blade to mechanically lift those tracks. They can't! That's why front mount mowers and ZTR's out-cut everything. The designer can tweak the front caster wheel placement to coincide with the back sweep behind it.

 

[rockinbbar]

I retired from John Deere... put many tractors and mowers into production over the years. It's ok to disagree. ;<)

I'm not saying tip speed doesn't make a difference. I'm saying it's not the whole story and "faster is not always better".... you pay a big price in power concumption to swing the blades fast and often the cut is not improved.... especially if you bog in tough cutting (finish or rotary cutters).

I little secret: spindle placement is HUGE. Tire tracks from the power unit push the grass forward and mash it down. If mid mount and rear mowers designers had their way... they'd place the 'back sweep' side of the mower blade to mechanically lift those tracks. They can't! That's why front mount mowers and ZTR's out-cut everything. The designer can tweak the front caster wheel placement to coincide with the back sweep behind it.

Yeah, I tend to match the horsepower with the cutter, to minimize slowdown and maximize cut performance.

But I do several things as well. Ground speed, keep blades razor sharp, corners blunted, and turn direction of tractor adhered to. Small things make a difference.

Big change in performance and cut with my HD cutter when I went from 100hp to 120. For the vast majority of my projects, the added horsepower allows me to cut without lugging the engine, and slowing the cutter.

 

[dieselscout80]

But I do several things as well. Ground speed, keep blades razor sharp, corners blunted, and turn direction of tractor adhered to.

Question what do you mean by turn direction adhered to?

 

[rockinbbar]

Question what do you mean by turn direction adhered to?

On a good cutter, all 3 cutting decks don't turn the same rotation direction, so when you turn one way or the other, you may notice a poorer cut.

Mine cuts better when I make a turn, or circle a tree counter clockwise. The only difference would be the direction the blades are spinning.

I also try and not turn too sharp, as the main drive shaft gets more pressure on it from a sharp turn, than a gradual turn. Those CV joints and shafts are expensive, and I litterally slather the CV joint with grease daily to cut down that wear. Last one made it 11 years and was still tight.

 

[dadohead]

On a good cutter, all 3 cutting decks don't turn the same rotation direction, so when you turn one way or the other, you may notice a poorer cut.

They counter-rotate the blades to mechanically "back-sweep" the tire tracks. In a turn though, the tire tracks can run out of the back sweep and move into the forward sweep portion of the cut. The tire tracks arent cut well and stand back up in a few days. No amount of tip speed can fix it either. Spindle placement is huge!

 

[rockinbbar]

They counter-rotate the blades to mechanically "back-sweep" the tire tracks. In a turn though, the tire tracks can run out of the back sweep and move into the forward sweep portion of the cut. The tire tracks arent cut well and stand back up in a few days. No amount of tip speed can fix it either. Spindle placement is huge!

Tip speed and spindle placement seem to be your strong points.

Please inform me as to my options on spindle placement in the field cutting brush. Not sure why you think that I believe tip speed fixes anything, other than I'd rather have a higher blade tip speed, all other things equal.

And yes, my tractor pulls my batwings, so how do I avoid them pushing the grass down as I mow with a tandem pulled cutter?

I do have a front mounted cutter for my CTL. 6 foot Modern Ag. I reckon I can position that spindle in front, but am unsure of the tip speed because it varies depending on the hydraulic flow of the machine. But it sure doesn't cut nearly as good as my batwings do.

 

[dadohead]

But it sure doesn't cut nearly as good as my batwings do.

Ha, you can't compare mowers unless they are set to the same HOC, run at the same ground speed, and cut in the same grass side-by-side. I'm done here... good luck.

 

[MtnViewRanch]

How about a Bush Hog 12' cutter?

3112 Flex-Wing Rotary Cutter - Bush Hog

bushhog.com

There used to be a guy on the tractor forms who cut highways for a living. All he used were Bush Hog brand mowers

 

[Brown Dog]

I absolutely don't agree with you that blade tip speed doesn't make a difference … When shredding ranches with 3-5 foot of brush growth, a higher blade tip speed means that I get a cleaner cut, and have to circle back less often to cut down the stragglers …

I totally agree with you.

I had to over rev my JD MX10 to get it to cut good.

My BH 2815 with faster BTS cuts way smoother.

I’m all about a faster BTS in all my grass cutting eqpt

 

[rockinbbar]

Ha, you can't compare mowers unless they are set to the same HOC, run at the same ground speed, and cut in the same grass side-by-side. I'm done here... good luck.

Thanks so much for your engineering contributions to this thread!

Yeah, I know you can't compare cut on a CTL front cutter and a batwing cutter... That would be like comparing finish mowers cutting country club greens to batwing cutters shredding pastures.

I just put that out there because I, or anyone else don't have many options about "spindle position" when pulling a batwing cutter... which is what this thread was about from the onset.

Have a great day!

 

[dieselscout80]

On a good cutter, all 3 cutting decks don't turn the same rotation direction, so when you turn one way or the other, you may notice a poorer cut.

Mine cuts better when I make a turn, or circle a tree counter clockwise. The only difference would be the direction the blades are spinning.

I also try and not turn too sharp, as the main drive shaft gets more pressure on it from a sharp turn, than a gradual turn. Those CV joints and shafts are expensive, and I litterally slather the CV joint with grease daily to cut down that wear. Last one made it 11 years and was still tight.

Thanks for explaining it.