Flail Mower Hammers or Y knives

[allen in texas]

Cool Greg. Now that we've got that out of they way, let's fight over our tractors. Orange vs Green. LOL

 

[greg_g]

No fight, but perhaps a question. My JD has a Yanmar engine, but was assembled in and shipped from their Georgia plant. But I don't know much about which Kubota models come from where. Is your Kubota US-made as well?

//greg//

 

[allen in texas]

I understand that My Kubota is built in the US. Not sure though. It is however, all Kubota. That's an interesting question. I'm going to research and find out.
Just FYI, I wanted a JD. My JD dealer here couldn't match the deal I got from Kubota on comparable tractors. That being said, I really like my tractor and will probably stay with Kubota from now on.


Well now, a quick search reveals that the Kubota tractors sold in the U.S., although originally from Japan, are now manufactured and assembled in the good ole US of A

 

[Howard Farm]

No PTO on the front. I don't have the requireement yet. Can rotate the steering etc to face backwards if I had a flail mulcher or slasher that I wanted to push rather the trail. Still have n't played with it yet.

 

[leonz]

I understand that My Kubota is built in the US. Not sure though. It is however, all Kubota. That's an interesting question. I'm going to research and find out.
Just FYI, I wanted a JD. My JD dealer here couldn't match the deal I got from Kubota on comparable tractors. That being said, I really like my tractor and will probably stay with Kubota from now on.


Well now, a quick search reveals that the Kubota tractors sold in the U.S., although originally from Japan, are now manufactured and assembled in the good ole US of A

The motor and the transmission come from Japan and everything else is procurred
here or in canada and exported to europe etc. It explains a lot of the quality control issues.

 

[lochart]

Hi, I have been using hammers and have been happy with the results on pastures, i have however been wondering if i would have better results with y knives. Stay sharper longer and perhaps get better re-growth?

 

[AGTtactical]

Hi, I have been using hammers and have been happy with the results on pastures, i have however been wondering if i would have better results with y knives. Stay sharper longer and perhaps get better re-growth?

Curious about this too. Hammers are great until they get wear on them...as the front wears, the hammer tip becomes thicker and thicker, to the point where they really don't cut, but just beat and ear grass. I wish Landpride's flail allowed you to change from hammers to other types without changing the whole rotor.

 

[AGTtactical]

Yes Greg, I am a flail owner. Not trying to argue but I'd be glad for you to show me how to make a flail that has the "V" Or "Y" knives (my flail in fact) cut without leaving "serrations" in the grass. My flail has 4 rows of knives. I have cut my lawn with it. It looks good but it leaves the lawn "serrated" no matter what height I cut the grass. It's the nature of the beast. Some one here said, when using their "V/Y" knife equipped flail to mow a lawn "Looked liked it had been combed. There is no way IMO to get a smooth cut on grass with blades that have approximately 45 degrees of angle relative to the ground. The overlap of the knives is such that the serrations are only about an inch wide but they will be there no matter how my flail is set up.

I think you are correct about Y blades leaving serrations...I've seen too many people claim that they have the same problem, even people who are actually in the business of repairing and maintaining flails. Some people don't notice the serrations because they let their grass get tall, so the clippings hide it. But if you keep your grass cut, and think most people will notice it. I imagine it may be less noticeable with some makes than others.

 

[AGTtactical]

That said, I use yet a different type knife, something of a cross between your 920 and 946 knives. So in retrospect, I guess mine may more appropriately be described as a "T" rather than a "Y". Three rows of 11 uni-directional double edged knives, each 2.6" wide overall, with right and left cutting edges. There are 66 edges that cut a 74" swath. But if you consider that 33 x 2.6" = 85.8", you can see that works out to quite an effective overlap.
//greg//

Well, there you go...a T shape would certainly have an entirely different cut, and they probably made them that way because they eliminate serrations. They probably are much more expensive to make them strong enough to handle the stress of a 90 degree angle. Not sure why more manufactures don't offer this option.

 

[vlcakc]

The old NH 918H flail with Y-blades I used for 16 years did not leave serrations, the new Land Pride FM2584 with Y-blades does leave serrations. The difference? The number of rows of blades was far greater on the NH 918H than the FM2564. I used to use the NH918H on residential lawns and the cut was just as smooth as the zero turn mower. I only used the FM2584 with Y-blades on a lawn once before abandoning the practice.

I recently changed the blades on the FM2584 from the Y-blades to hammer blades without changing the rotor as recommended by Land Pride. Land Pride balances the rotor and blades as a unit and cautions that changing the blades only can cause an unbalance. I guess I was lucky, because the hammer blades run smoothly and have no more vibration than the Y-blades did. I mowed a 10-acre hay meadow with 12"-18" of last year's growth of Blue Stem grass and was pleasantly surprised by the smoothness of cut. I then made some test cuts on a lawn area with very good results. Will the hammer blades continue to give a smooth cut on lawn grass after they dull some from use? Don't know yet. I plan to use the flail on a pasture improvement project with some substantial brush areas to clear, so the hammer blades will probably be dulled some. Be interesting to see how the used hammer blades do on lawn areas. Vic

 

[leonz]

Well, there you go...a T shape would certainly have an entirely different cut, and they probably made them that way because they eliminate serrations. They probably are much more expensive to make them strong enough to handle the stress of a 90 degree angle. Not sure why more manufactures don't offer this option.

========================================================================================================================================================================================================================


The reason you see serrations when mowing at a low height with a flail mower is due to the fact the almost every flail mower rotor made has mounting stations that are narrow and they have enough width between the station mounts to permit the installation of the knife pairs.

The flail mower rotors with the mounting loops/D rings permit the manufacturer to purchase short knives to fit out the flail mower and it also allows the manufacturer to mount the scoop knife/duck foot knife on them as well to enable the user to mow heavy brush and also mow fine grass but it leaves a waffle pattern unless the user mows at right angles to overlap and cut the grass again to achieve a nicer look.

This also allows the use of side slicer knives that have elongated mounting holes which allows them to become airfoils and permit them to mow a wider cut with overlap with the knife pairs following behind them to mow any grass that the preceding pair misses. This is why in the first instance you see flail mower rotors with 3 rows of mounting stations with a wider space between the mounting stations on each row.

These same flail mower rotors also have additional mounting holes to add more knife mounting stations to use more side slicer knife pairs when mowing good sod.

The flail mower knives that are considered scoop knives are sheared, punched for two mounting holes, rolled and formed so the elongated or round mounting holes meet to
create a thicker steel mounting point then the cutting edges are ground, then heat treated. There are scoop knives that are nit heat treated just like some side slicer knives.

The only down side for a hammer knife or scoop knife is that they will not recut the clippings UNLESS they are dry and brittle and have little weight if they have not been weighted down with rain and begin to choke out the good grass on lawns.

 

[doneill127]

I have a Woodmaxx FM54 with the Y blades. it works great cutting tall grass weeds and light brush. I did a review with pictures last year. Occasionally I use it to cut my lawn and it it does leave serrations or rows but I expected that because it痴 cutting in the shape of the blades. I did a lot of research before buying the Woodmaxx and found that there are fine cut and regular cut rotors with Y blades. If you want a nice finish lawn cut get something like a Caroni with the finish rotor it has double the number blades of the standard rotor or the equivalent sized Woodmaxx. There is a penalty in the fine cuts takes more horsepower especially if it痴 going to be used for brush cutting because of the increased number of blades.

 

[AGTtactical]

========================================================================================================================================================================================================================


The reason you see serrations when mowing at a low height with a flail mower is due to the fact the almost every flail mower rotor made has mounting stations that are narrow and they have enough width between the station mounts to permit the installation of the knife pairs.
The flail mower rotors with the mounting loops/D rings permit the manufacturer to purchase short knives to fit out the flail mower and it also allows the manufacturer to mount the scoop knife/duck foot knife on them as well to enable the user to mow heavy brush and also mow fine grass but it leaves a waffle pattern unless the user mows at right angles to overlap and cut the grass again to achieve a nicer look.
This also allows the use of side slicer knives that have elongated mounting holes which allows them to become airfoils and permit them to mow a wider cut with overlap with the knife pairs following behind them to mow any grass that the preceding pair misses. This is why in the first instance you see flail mower rotors with 3 rows of mounting stations with a wider space between the mounting stations on each row.
These same flail mower rotors also have additional mounting holes to add more knife mounting stations to use more side slicer knife pairs when mowing good sod.
The flail mower knives that are considered scoop knives are sheared, punched for two mounting holes, rolled and formed so the elongated or round mounting holes meet to
create a thicker steel mounting point then the cutting edges are ground, then heat treated. There are scoop knives that are nit heat treated just like some side slicer knives.
The only down side for a hammer knife or scoop knife is that they will not recut the clippings UNLESS they are dry and brittle and have little weight if they have not been weighted down with rain and begin to choke out the good grass on lawns.

Thanks Leonz, but previously you said serrations were caused by improper height.

"If you are getting serrations when mowing the mower is set too low."

Did you do a little research since then? Anyhow, I think we all know that more overlap will obviously reduce or eliminate serrations. Yes, some rotors don't have enough overlap to reduce serrations, but the problem is still caused by the Y blade design, i.e. a Duckfoot blade, T-blade, or hammer of the same width and length mounted on the same rotor with the same mount spacing will not have serrations, while a Y blade may have them. That sounds like a blade problem to me. One only has to visualize a Y blade cutting grass to see that its impossible or such a blade to not cut in a serrated "^" shape, unless that blade is followed with enough overlapping cuts behind it to eliminate the inverted V shape left by the first blade.

 

[AGTtactical]

I have a Woodmaxx FM54 with the Y blades. it works great cutting tall grass weeds and light brush. I did a review with pictures last year. Occasionally I use it to cut my lawn and it it does leave serrations or rows but I expected that because itç—´ cutting in the shape of the blades. I did a lot of research before buying the Woodmaxx and found that there are fine cut and regular cut rotors with Y blades. If you want a nice finish lawn cut get something like a Caroni with the finish rotor it has double the number blades of the standard rotor or the equivalent sized Woodmaxx. There is a penalty in the fine cuts takes more horsepower especially if itç—´ going to be used for brush cutting because of the increased number of blades.

Interesting. The nice thing about Woodmax is that you can change blades without changing rotors. Have you tried their duckfoot blades (aka hammer and "H" blades depending where you look on their website). I'll look for your review...

View attachment 602112View attachment 602113.

 

[leonz]

The scoop knives or hammer knives do not have as sharp a cutting edge as the side slicers.

You can create serrations when you mow at one inch or if your flail mower has thatching blades centered between the side slicer knife pairs as the flail mower must be lowered to a one inch height to allow the thatching blades to pull the thatch out of the sod and also create the groves needed so you can overseed to create a thicker turf after the thatch is removed.

With the mounting stations as they are with narrow gaps between the two weldments for each mounting station to mount the side slicer pairs and hold them from sliding from side to side. this creates the serrations if you look close enough at the turf or when you have a flail mower rotor with two rows of mounting stations or three rows of mounting stations where the flail mower with 4 rows of mounting stations will continue to clip the grass as the knife stations overlap at 2200+- RPM.
You take my flail mower rotor in the example and it is a tool less system with a spring tensioned loop that holds the side slicers and the thatching knife in place and the short length side slicer knife being three inches and its punched elliptical mounting hole allow it to become an airfoil when the flail mower rotor creates enough centrifugal force to allow it to fully level out and create an even cut across the flail mower rotors cutting width.
This design makes for a perfect verticutting method to mow good sod or brush with a finish flail mower. you have to mow more a bit more slowly but you can over lap and recut the clippings to make them smaller so that the clippings will dissolve sooner and not cause dead spots from grass or brush being left on the ground.

 

[AGTtactical]

I doubt serrations are caused by cutting at 1". The same serrations are likely there in taller grass too...you just don't notice it as much as when the cut is so close to the ground, as you can likely see thatch or even soil when the grass is only 1" tall at the low part of the serrations.

 

[doneill127]

Here’s the review. Woodmaxx FM54 Flail mower review

 

[AGTtactical]

Here’s the review. Woodmaxx FM54 Flail mower review

Doneill, that is AWESOME!! Thanks!

 

[AGTtactical]

I only used the FM2584 with Y-blades on a lawn once before abandoning the practice.

I recently changed the blades on the FM2584 from the Y-blades to hammer blades without changing the rotor as recommended by Land Pride. Land Pride balances the rotor and blades as a unit and cautions that changing the blades only can cause an unbalance. I guess I was lucky, because the hammer blades run smoothly and have no more vibration than the Y-blades did. I mowed a 10-acre hay meadow with 12"-18" of last year's growth of Blue Stem grass and was pleasantly surprised by the smoothness of cut. I then made some test cuts on a lawn area with very good results. Will the hammer blades continue to give a smooth cut on lawn grass after they dull some from use? Don't know yet. I plan to use the flail on a pasture improvement project with some substantial brush areas to clear, so the hammer blades will probably be dulled some. Be interesting to see how the used hammer blades do on lawn areas. Vic

This is some great info. Note this too from Landpride's website:

"Knife tip speed 12,046 fpm provides a clean cut, creates a vacuum effect when using hammer or ducksfoot blades..." They omit the Y blades from this assessment... It appears from the Landpride photos that their hammers are somewhat of a cross between duckfoot and hammers...they look very similar, accept that the hammers are bigger.

FM25 Series Flail Mowers | Land Pride

 

[leonz]

I doubt serrations are caused by cutting at 1". The same serrations are likely there in taller grass too...you just don't notice it as much as when the cut is so close to the ground, as you can likely see thatch or even soil when the grass is only 1" tall at the low part of the serrations.

========================================================================================

As I mentioned previously the serrations saw tooth patterns created in verticutting occur due to fact that the side slicers are held in place within the narrow width of each mounting station and as they do not use a D ring loop mount that would permit a side slicer with the elongated mounting holes to become an air foil when they are spun up to 2200RPM+- .

This was an engineering decision by these manufacturers as it allowed them to use a smaller piece of hollow round stock as the flail mower rotor.
This decision also eliminated the opportunity to use a larger diameter flail mower rotor made from formed rolled sheet steel that is welded to the end discs that have the shaft stubs mounted to them. The end result was that some side slicer knives are required to be much much longer than they needed to be.

This decision also eliminated the opportunity to use pressure gradients to their maximum advantage to aid in mowing by using a pair of air paddles.

The use of a pair of air paddles mounted on the flail mower rotor increases the amount of lift/ suction, negative pressure gradient created when mowing.

This increases the available suction/negative pressure gradient to lift the brush and grass that needs to be mowed and also lift the clippings enable the side slicers to lift and clip them up a second or third time to shred them into a fine mulch that will melt back into the soil quickly.