Flail Mower Let's talk flail mowers

[leonz]

Hello John,

So what you are telling is that you have taken the time to move the drive pulley, driven pulley, cross shaft, and frame mounting plate for the drive pulley and belt tensioner and moved them to the opposite side today and mowed once more???


The thing is the rotary mower blades are operating at up to 20000 feet per minute tip speed or more to create the lift to tear at the grass blades.

The thing I do not understand is the PTO is rotating counterclockwise rotating the right angle gearbox shaft counterclockwise even with the gearbox being flipped over.

 

[jthibodeau89]

Is gearbox ratio correct for 540 rpm pto? My JD flails have both 540 and 1000 pto gear box ratios available.

Though you don't have a tach, you can calculate the pto ratio to estimate rotor rpm.

 

[John0829]

Hello John,

So what you are telling is that you have taken the time to move the drive pulley, driven pulley, cross shaft, and frame mounting plate for the drive pulley and belt tensioner and moved them to the opposite side today and mowed once more???


The thing is the rotary mower blades are operating at up to 20000 feet per minute tip speed or more to create the lift to tear at the grass blades.

The thing I do not understand is the PTO is rotating counterclockwise rotating the right angle gearbox shaft counterclockwise even with the gearbox being flipped over.

To change the rotation on this flail you open the gear box and move the drive gear from one end of the input shaft to the other end so that the driven pinion will now rotate in the reverse. In other words the drive gear is moved from in front of the driven pinion to the back of it. Doesn't take long after you figure out how to get the gear to slip in behind the pinion.

I never finished mowing the other day since I became SO disgusted with the tire strip being left. I just had to walk away from it for awhile. I was going to use the finish mower to complete this weeks mowing but then decided the only thing that had not been tried was changing the rotation of the rotor so that it would spin in the same direction as Alamo/Mott flails advertise they turn. Plus I read an article written by Mott back in 1971 about flails and in it he commented on why the use of forward or tire direction rotation to pickup laid over grass. So I figured what did I have to loose other than the time it took to make the gear box change, I can change it back in about an hour if needed now that I have figured out the tricks. While I was into it I also verified every adjustment and setting, belts, skids, flail movement, etc. to be absolutely sure everything was as the manual dictates.

As I said it did cut marginally better but still is leaving a strip even though I was cutting at about 3 mph, the manual recommends 5 mph and even tried running the flail at more than 540 PTO to see if over speeding it would make a difference. I have one other idea but will have to wait until the grass is ready to mow again, that is to change the slicers from the area that is leaving the strip with some that are not. To see if it has something to do with wear but I do not think it will since the strip moves with the mower setup as offset or centered. With it centered I had 2 strips instead of one but then that was before all the sharpening and other adjustments were made.

 

[TheFarmerInAdell]

You have a 918H, what you need is a 918L. The 918L is for finish mowing. There are more stations on the rotor. There will be more overlap of the stations and therefore a finer cut. Otherwise you can look at selling and getting a Ford 917 that you can change between rough cut and fine cut (or use the scoops to do both) or a Alamo/Mott that is a fine cut version. Basically you have a mower designed for rough cutting and you're expecting it to do fine cutting. Look for a mower that has more stations closer together with narrower knives to accomplish what you're after.

 

[troverman]

Yeah, I agree. The pics posted show a fairly nice finish lawn. I don't think I'd even try to mow that area with a flail mower, but if I did, I wouldn't expect a perfect finished cut. The side slicer knives seem to be useless to me - less quality cut with seemingly zero advantages over a scoop or even hammer knife.

 

[leonz]

To change the rotation on this flail you open the gear box and move the drive gear from one end of the input shaft to the other end so that the driven pinion will now rotate in the reverse. In other words the drive gear is moved from in front of the driven pinion to the back of it. Doesn't take long after you figure out how to get the gear to slip in behind the pinion.

I never finished mowing the other day since I became SO disgusted with the tire strip being left. I just had to walk away from it for awhile. I was going to use the finish mower to complete this weeks mowing but then decided the only thing that had not been tried was changing the rotation of the rotor so that it would spin in the same direction as Alamo/Mott flails advertise they turn. Plus I read an article written by Mott back in 1971 about flails and in it he commented on why the use of forward or tire direction rotation to pickup laid over grass. So I figured what did I have to loose other than the time it took to make the gear box change, I can change it back in about an hour if needed now that I have figured out the tricks. While I was into it I also verified every adjustment and setting, belts, skids, flail movement, etc. to be absolutely sure everything was as the manual dictates.

As I said it did cut marginally better but still is leaving a strip even though I was cutting at about 3 mph, the manual recommends 5 mph and even tried running the flail at more than 540 PTO to see if over speeding it would make a difference. I have one other idea but will have to wait until the grass is ready to mow again, that is to change the slicers from the area that is leaving the strip with some that are not. To see if it has something to do with wear but I do not think it will since the strip moves with the mower setup as offset or centered. With it centered I had 2 strips instead of one but then that was before all the sharpening and other adjustments were made.

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Hello John,

SO, what you are saying is you have a 917 flail mower with the driven round spur gear and the beveled drive pinion gear and not the one to one right angle bevel gearbox?

I would remove the three overlapping knife sets that create the two sets of mohawks and resharpen them and then remount them rather than just change knife locations.

 

[TheFarmerInAdell]

Yeah, I agree. The pics posted show a fairly nice finish lawn. I don't think I'd even try to mow that area with a flail mower, but if I did, I wouldn't expect a perfect finished cut. The side slicer knives seem to be useless to me - less quality cut with seemingly zero advantages over a scoop or even hammer knife.

Side slicers are going to be tougher than the scoop knives and can handle woody materials better. I had scoops (wings, actually) and switched to side slicers. Lower quality finish, but they do better on brushy stuff. They also handle hard impact (rocks) better than hammers. They have their place in the line-up, but everyone has their own needs and should get what fits their needs best. In my case the side slicers work best because rocks don't bother them much and they cut the brush down.

 

[troverman]

Side slicers are going to be tougher than the scoop knives and can handle woody materials better. I had scoops (wings, actually) and switched to side slicers. Lower quality finish, but they do better on brushy stuff. They also handle hard impact (rocks) better than hammers. They have their place in the line-up, but everyone has their own needs and should get what fits their needs best. In my case the side slicers work best because rocks don't bother them much and they cut the brush down.

I was cutting a field with a lot of fairly short (2 feet - 3 feet tall), thin, woody stalks growing in amongst the field grass. The side slicers simply don't cut these thin stalks down, and the end result looks poor. The scoop knives knock down all of it. As for rocks, you may be right - I never lost a side slicer. I have lost scoops, but on my Vrismo they are pretty easy to change out.

 

[Fallon]

I was cutting a field with a lot of fairly short (2 feet - 3 feet tall), thin, woody stalks growing in amongst the field grass. The side slicers simply don't cut these thin stalks down, and the end result looks poor. The scoop knives knock down all of it. As for rocks, you may be right - I never lost a side slicer. I have lost scoops, but on my Vrismo they are pretty easy to change out.

I had surprisingly good results with the side slicers on my $100 917. They did good on brush up to finger size. Beyond that they just made a racket & debarked things. I lost a few to rocks & a well head, but they survived many other smaller rocks.

How heavy were your scoops compared to the side slicers? Weight is going to give you an advantage on bigger heavier material than most other factors. The 5lbs? hammers on my Peruzzo Brush Bull are pretty rounded on the cutting edge at this point, WAY more than my 917 thin side slicers could ever get. Unsurprisingly the hammers cut brush & wood way better. Surprisingly it cuts grass about as well. A hair less mulching & recutting, but a very good cut for a field, probably even almost to lawn standards.

 

[John0829]

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Hello John,

SO, what you are saying is you have a 917 flail mower with the driven round spur gear and the beveled drive pinion gear and not the one to one right angle bevel gearbox?

I would remove the three overlapping knife sets that create the two sets of mohawks and resharpen them and then remount them rather than just change knife locations.

No it is a 918H, the gear box is way different than the 917 uses as you can see in the pic. I have decided that I am expecting more from this mower than it can deliver and am throwing in the towel. After all the sharpening, adjusting, resharpening and re adjusting, plus now I am finding parts availability is limited, should have done more research. I'll hold on to it until I find something else since it being an offset does OK on the county road that I keep the shoulders cut on since the county can seldom be bothered to cut them.

I am not expecting it to cut like the finish mower a bit rougher cut is fine since it is a large area that is kept cut for the appearance of the property. But the mohawks of uncut grass standing up are just not acceptable although reversing the rotor rotation did improve it somewhat. The old King Kutter bush hog with sharp blades will do a better job than the flail has so far.

I really appreciate all the help and comments, thank you all. I just got burned on this one, my mistake thinking New Holland would be a top quality product, I do have to say at least it is solid and well built. I will have to do more and better research before getting another, if I do. There are many things about flails I like, just not the quality of cut. At least not the cut from this one.