Flail Mower Let's talk flail mowers

[leonz]

You mean cup knives I think and you need shackles
as they are shorter in total length.


Nothing short of a new (P) rotor and shackle hangers;


How fast is your engine speed while mowing?
Is the engine running at a high RPM to maintain a
very high rotor speed?

The rotor speed may surpass 100 MPH at 540 RPM
with no lugging.

Do you or overlap while mowing? you can reduce your
forward speed to get a finer cut.

Have you looked at the knives to see if they need to be
flipped if you have twin knife edges.

 

[beppington]

You mean cup knives I think and you need shackles
as they are shorter in total length.

Ah, OK, then has anybody successfully changed to those?

Nothing short of a new (P) rotor and shackle hangers;

There are no hammers or cup knives that can be swapped onto the Caroni OEM rotor?

How fast is your engine speed while mowing?

2550 RPM

Is the engine running at a high RPM to maintain a very high rotor speed?

I run the engine at 2550 RPM in order to achieve a PTO speed of 540 RPM, as instructed by my tractor's manual.

Do you or overlap while mowing? you can reduce your forward speed to get a finer cut.

I overlap by probably a foot or so just to be thorough, but I don't usually purposely mow the entire area twice. And I mow at a relatively slow speed, IMO. I don't know the actual speed but will check it next time.

Have you looked at the knives to see if they need to be flipped if you have twin knife edges.

The knives are new & look just fine. I just think the horizontal blade angle of cups or hammers, running level to the ground, makes more sense than the OEM knives running at an angle to the ground. It does a very good job as-is, I just think it would be even better with the cutting edges running parallel to the ground.

 

[leonz]

flail mower saga continues

Ah, OK, then has anybody successfully changed to those?



There are no hammers or cup knives that can be swapped onto the Caroni OEM rotor?


Not the F rotor unless you plan on a modified shackle sans connecting chain link that is long enough to pass through and swing and then still screw the lock link together.
Plus I dont know if the guage roller would raise the mower hood enough to allow it to work properly.




I overlap by probably a foot or so just to be thorough, but I don't usually purposely mow the entire area twice. And I mow at a relatively slow speed, IMO. I don't know the actual speed but will check it next time.



The knives are new & look just fine. I just think the horizontal blade angle of cups or hammers, running level to the ground, makes more sense than the OEM knives running at an angle to the ground. It does a very good job as-is, I just think it would be even better with the cutting edges running parallel to the ground.

About the cup knives:
They may ding up bit faster and will wear a bit faster and thats the only issue with the cutting edge; but having enough lacing width for the knives and hangers will be an issue due to the cutting width possibly leaving stripes with an F rotor-whoopsie:laughing:


Dont forget the grass slicer knives are an airfoil and the Y part will be nearly flat if I remember the aerodynamics of the cutting surface, as the lower flat part at the bend becomes near level due the leading edge aerodynamics of the area of the cutting edge while educing its resistance and creating the wing and flat cut effect.

I think thats how it goes anyway as the individual knive blade is also resisting the air mass and air volume under the hood of the mower, until the leading cutting edge encounters the oncoming air pressure gradient created by the rotation speed of the rotor weldment and knives.

Thats the nice thing about the 3 inch tapered knives as they cut faster with less air resistance the suction the staggered rotor creates is huge-If i get ambitious I will see about borrowing an airflow meter and Hg. gauge.
leonz

 

[Bl8tant]

I posted the following in another thread: (see bottom of post for a review of todays mowing)

I recently bought a used 78" cut John Deere 25A flail mower for $500. I put all new finish cut blades (the ones that look like a ducks foot), hangers, clevis, etc on it. I also replaced both rotor bearings and one roller bearing. Painted it, and put on new decals. All told, I have around $900 (and about 20-30 hours) in it and looks like new again. Out of curiosity I priced a new one (it's still in production) on the JD website....$4700!

So how did it perform? I love this thing! It sounds like a giant vacuum cleaner (much quieter than our brush hog), the cut quality is amazing. In moderately tall grass it looks like it was mowed with a riding mower, but without any clumps or winrows. The cut quality in short grass looks pretty good, but not as clean as taller grass. I have not tried it out in some of the brushy areas, as I don't want to damage the new blades (yet).

The mower is used with a Kubota L3830 (38hp). Even in dense 12" grass going up a steep hill, my RPMs barely dropped.

For mowing large areas of dense grass and LIGHT brush, I can't think of anything better. This has been one of best purchases I've made.



Todays mowing:
Tall, thick field grasses - WOW, nice finish cut, much faster than the old 4' BH

Shorter (5"-8") "lawn" area - decent finish, just looks different than when I use the riding mower, obviously faster, ROPS trimmed a few trees for me.

Overgrown area with some small brush (less than 1" diam) - chewed everything to bits, mower sounds like a dryer filled with shot putt but didn't even slow down. Made me rather nervous about damaging those shiny new blades, but they looked fine afterwards.

6" log in tall weeds that I didn't see - this made HORRIBLE sounds, mower kept chewing away until I managed to collect my thoughts and kill the pto, change underwear, inspect mower for damage....none found.

Overall, I'm still very impressed. I will definitely reserve the brush cutting for the brush hog. For mowing tall unkept grassy areas...the flail mower will never get a days rest.

 

[dieselscout80]

I've read most/ all of this thread over the past few months but can't remember if anyone has successfully changed out their Caroni TM1900's OEM knives for hammers?

If so, where did you get the materials (hammers, shackles, bolts, nuts, anything else)?

And, how did it work out?

I noticed in Land Pride's catalog their smaller/ lighter flails have knives, & only their biggest flail has hammers. This would seem to imply that high(er) HP is needed for hammers? (I have 40.5 HP total/ 31.5 PTO HP)

I'm not looking to cut anything larger than the OEM knives can cut, just looking for an even smoother lawn cut. It's pretty darn good as-is, but it would seem that hammers, with their horizontal blade, would cut more uniformly than the angled OEM knives.

Maybe look into these Ford 917 knives/blades.

 

[sodamo]

Noticed that from time to time there's questions regarding flail cut so as I mowed today I figured I'd post something of a before and after pic.
In the attached pic you can see where I was mowing today. It used to look like the area to the right outside the fence. Not too bad for former cane field turned pasture.

 

[KRBrouwer]

"Dont forget the grass slicer knives are an airfoil and the Y part will be nearly flat if I remember the aerodynamics of the cutting surface, as the lower flat part at the bend becomes near level due the leading edge aerodynamics of the area of the cutting edge while educing its resistance and creating the wing and flat cut effect.

I think thats how it goes anyway as the individual knive blade is also resisting the air mass and air volume under the hood of the mower, until the leading cutting edge encounters the oncoming air pressure gradient created by the rotation speed of the rotor weldment and knives. "

The centrifugal force developed at 540 rpm is much, much greater than any aerodynamic resistance. If you have the Y blades, and look back after cutting, you will clearly see the Y shape in the grass. They do not cut flat.

Ken

 

[leonz]

"Dont forget the grass slicer knives are an airfoil and the Y part will be nearly flat if I remember the aerodynamics of the cutting surface, as the lower flat part at the bend becomes near level due the leading edge aerodynamics of the area of the cutting edge while educing its resistance and creating the wing and flat cut effect.

I think thats how it goes anyway as the individual knive blade is also resisting the air mass and air volume under the hood of the mower, until the leading cutting edge encounters the oncoming air pressure gradient created by the rotation speed of the rotor weldment and knives. "

The centrifugal force developed at 540 rpm is much, much greater than any aerodynamic resistance. If you have the Y blades, and look back after cutting, you will clearly see the Y shape in the grass. They do not cut flat.

Ken

Hello Ken,

do you have a 2 row or a 4 row rotor?


Yes you are right about the aerodynamics of the mower knives.

My 4 row staggered knive rotor cuts absolutely flat with the tapered knives

all the time even in brush.


I always laugh when people tell me a zero turn mower cuts better than any other mower; I just walk away smiling because my turf is better and not damaged by blades that tear and shock the grass at 18,500 rpm.

 

[beppington]

The dolly I made for my dad's Caroni TM1900. Two ~82"-long 4x4's connected with two short pieces of 4x6's I had leftover laying around. Piece of 2x8 as a back-stop to set the roller against. Two short 2x8 pieces under the front corners, to keep the flail level & keep it from rolling forward. The level my dad has his roller set at takes a two-by (1.5") under the front corners to just about perfectly level the unit (front-to-back).

 

[J_J]

leonz,

The number you quoted for rpm, should be the fps number, otherwise, velocity in feet per second. You can not get that high a bld tip velocity or rpm using a flail mower. There are some finish mower flails that will cut as good as any mower that is using sharp blades.