Flail Mower Let's talk flail mowers

[TerryCC]

Couple of points regarding substitution of Flailmaster clevises for Caroni. 1) the Flailmaster clevis is wider than the Caroni mount and needs to be narrowed to fit. I'm pretty good at it now but the first time will take you a while. I crush the arms together in a big vise and then use a flap disk to remove about 1/16" from each shoulder so the clevis can move freely in the mount.

2). Although I have broken dozens of Caroni clevises over the years, I've never broken a Flailmaster clevis. I have broken knives mounted on a Flailmaster clevis (just once).

3) although the Flailmaster clevis is heavier, it seems fine to substitute. No noticeable imbalance.

Thought I would update on how the conversion from Caroni flails to FlailMaster flails went on my Caroni 1900. I disconnected the mower from the tractor and lifted it by the lower 3 point pins with my tractor's front end loader. The mower rolled over on its back and I used a jack stand on the upper 3 point mount to stabilize it, it was very stable and exposed the knives so that removal and replacement would be with me sitting on a stool rather than underneath.

I used an air ratchet and a box end wrench to remove the original bolts. A few nearly stalled the wrench, but the nuts all came off. I was prepared to cut them with a angle grinder if the air ratchet wouldn't remove them. This task took about 10 minutes.

I got the knives and clevises from FlailMaster, the same ones detailed in this thread and the 2-3/4 x 3/8 grade 8 bolts and grade 8 nylock nuts from Nutty. Nutty has an intuitive website and you can order online, FailMaster you have to call. The knives came in two days, the nuts in 4 days. I was concerned looking at the FlailMaster clevises are 7/16 and the bolts are 3/8 but the "looseness" is perfect. It was a pleasant experience with FlailMaster and I received a thank you note a week later.

The bending and shaving of the clevises is the time thief. I bent and shaved the first clevis several times before getting it to fit. Using it as a template I bent the other 32 (5 are spares). To my surprise most didn't fit. The welded ears on the rotating drum have a noticeable difference in spacing. Using a dial caliper I discovered that 1.500 inches would work at every station, so I rebent and shaved all 33.

Reassembly went fast and took less than 10 minutes to reinstall knives and clevises to all stations. Because of the difference in the width of the ears at each station, some nuts have a single bolt thread exposed and some are flush and a few are about one thread short of being flush. However all were caught by the nylon lock in the nuts. If I lose a station, it will be probably because not enough contact with the nylon locking material and the bolt.

I picked up the mower with the front end loader by the top attachment point and it rolled back over. Connected it to the tractor and engaged the PTO and seemed to work fine with any noticeable vibration. Earlier I had one station missing, the clevis and knives at one end of the drum right at the bearing. The vibration was noticeable and the noise of the mower was also noticeably different.

Couple of questions for Island Tractor. When you are bending the clevises in the vice, do you bend until the ears touch before releasing the vice? I didn't and am concerned about how much material I removed from the clevis to get a 1.500 in overall width. Second question: Are all your clevis bolts either flush or extend slightly from the nylock nut? In the industry I worked in, all bolts had to extend one thread past the nut to be approved for use.

 

[DavesTractor]

I've spent two days reading most of this thread and have decided to take the plunge on a flail. I have a Kubota L3240 hydro that claims about 26 Hp at the PTO. I would love to get a mower in the 6 -7 foot range to mower a couple 5 acre meadow that have been maintained with a rotary cutter for several years. Large sections of wild flowers I mow every other year and get 4 ft tall more or less. nothing over 1". Not looking for golf course cut, but something smoother than a bush hog would be nice.

I've been looking at the Phoenix SLE 140 and the Caroni 1900. I also found a good deal on a JD 25A used that seems in good condition, question is do I have enough tractor to pull the 7.5' flail.

Any advise is much appreciated.

If you are mowing 4' tall material, you need to be very conservative in mower width. I would mow all day long with your L3240 with a 6' and maybe even a 7' flail if it was regularly mowed and you were only cutting off a few inches of material. But a flail will want to chew up all of the material it cuts. It won't just lay it down, and that is why it looks so nice once cut. In your situation I would suggest a 5' flail. I am assuming the area will be fairly thick as well as tall. If it is tall and sparse, then go wider.

 

[leonz]

I've spent two days reading most of this thread and have decided to take the plunge on a flail. I have a Kubota L3240 hydro that claims about 26 Hp at the PTO.
I would love to get a mower in the 6 -7 foot range to mow a couple 5 acre meadow that have been maintained with a rotary cutter for several years. Large sections of wild flowers I mow every other year and get 4 ft tall more or less. nothing over 1". Not looking for golf course cut, but something smoother than a bush hog would be nice.

I've been looking at the Phoenix SLE 140 and the Caroni 1900. I also found a good deal on a JD 25A used that seems in good condition, question is do I have enough tractor to pull the 7.5' flail.

Any advise is much appreciated.

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

About your L3240;

turf or R4 tires?
liquid ballast in rear tires??
front end loader or suitcase weights in front?
How much time do you have to mow?


In order to mow well with a flail mower you need to have a lower cutting height and running in low range L1 or L2 when mowing as the flail mower creates a pressure gradient(suction/vacuum) to help lift and carry the clippings over the flail mower rotor.

The slower you mow the more effective the flail mower is for mowing as the clippings are cut shorter and recut as the mule advances into the brush. the clippings will also dissolve faster as well feeding the soil and not killing the grass from laying on the grass growing underneath.


Depending on how much time you have or can dedicate to this the thing is your going to want to mow more often since you have a small mule and it will take longer to clear to 2 inch height.

My father used his Ford Jubilee with loaded tires to knock down 12-15 foot goldenrod to reclaim 12 acres of old pasture to 2 inch cut on the first pass and he mowed 4 acres a week to maintain a 2 inch height on the 12 acres once he had the entire pasture knocked down after clearing all the heavy brush with the Jubilee and the 25A with finish cut/side slicer knives.

If you have loaded rears I would not hesitate to purchase the John Deere 25A IF you do not have slope mowing to contend with but keep in mind that the mowing will be slow in L1 or L2 until it is knocked down to 2 inches each time you mow.

AND you will be running in low range 2 or 3 at all time if you do not mow more than once per year.

Also JUST keep in mind a Caroni four foot flail mower with side shift will allow you to keep the mule at full power at all times and you can overlap as you mow.

The mules width of 59.6 inches is something you need to consider if you do not intend to have liquid ballast pumped into the rear tires or do not have loader to add front end weight if you purchase the JD25A or other wide flail mower as it will be more taxing on the mule since its a hydro drive mule. granted your mule has engine load sensors and will adjust the mule as it works but the four foot Caroni flail mower with side shift will require less power.

In my saying that your time is not at a premium for what you describe but having a 4 foot or five foot Caroni with the side shift will let you overlap and recut as needed as your going to spend a lot of time in the seat mowing each plot if you leave it un mowed regularly.

 

[Fallon]

A lot of the guys around here will say something along the lines of: "If you can lift it, you can spin it." I'm not sure about the other mowers, but my 25A weighs about 650lbs, give or take. Check the lift capacity of your machine, The "5-foot" rule is just a guideline, and I'd say you're close enough to it to get away with a 6' mower.

My L3200 lifted & spun my 7' Ford 917 flail. A Grand will lift more than my old economy machine, which had a no problems at all with that weight. HP wise it's about the same as my old machine. I did have to go a bit slower, but you should be doing that a bit anyway with a flail vs a rotary.

 

[DavesTractor]

A well balanced tractor mower package is nicer to operate than one that is right on the margins. I was spinning a 12' 2400 lb. Vrisimo with my 62 PTO HP tractor and it would do it, but tall grass made me slow down (I mow at 3.5-4mph) and if I had to lift and turn quickly it was all it would do to get it lifted and still keep the front end on the ground and not push straight when I wanted to go left or right. (yes, I have weights). I made it work, but I couldn't daydream and mow...I had to be really on it. Then I switched to a 10' 1500 lb. Vrisimo and it was a lot less work for me as the operator. Rarely had to change my pace and the tractor lifted the mower easily making sharp turns (mowing an orchard) a breeze. I'm a Vrisimo dealer, I can mow with any mower I want. Dropping back one notch worked better for me. Mowing 10 acres with a nimble 10' mower package vs struggling with the 12' mower took about the same amount of time. Just sharing that as a theory to consider.

And yes I thought about stepping up to a 80-100 HP tractor, but I only have 10 acres so that seemed a little overkill.

 

[troverman]

For two years I've mowed a 25-acre sloped field with a 4-foot Vrisimo flail mower on the back of my Kubota B2920...which has 21 PTO horsepower. I mow this field twice a year and usually see grass in the 1-2 foot range; some wild flower bushes but mostly field grass. The little Kubota did great! This year we've had tons of rain and warmth. The grass is in the 2-4 foot range and in one well watered area grass was 5-feet in height. Unfortunately the 29HP Kubota struggled to cut this height of grass even at wide open throttle. So I hooked the 4-foot flail mower to my larger Kubota L4310. It cuts through much better, but even a 4-foot mower on my 43HP Kubota struggled going through the tallest grass. So I would be very careful with the size you put on a 26 PTO HP tractor.

 

[DavesTractor]

For two years I've mowed a 25-acre sloped field with a 4-foot Vrisimo flail mower on the back of my Kubota B2920...which has 21 PTO horsepower. I mow this field twice a year and usually see grass in the 1-2 foot range; some wild flower bushes but mostly field grass. The little Kubota did great! This year we've had tons of rain and warmth. The grass is in the 2-4 foot range and in one well watered area grass was 5-feet in height. Unfortunately the 29HP Kubota struggled to cut this height of grass even at wide open throttle. So I hooked the 4-foot flail mower to my larger Kubota L4310. It cuts through much better, but even a 4-foot mower on my 43HP Kubota struggled going through the tallest grass. So I would be very careful with the size you put on a 26 PTO HP tractor.

If I may exaggerate, I think at some point of grass thickness/height even a 100 HP tractor could not spin a 48" mower. The mower is only designed to chew up so much material at a time. I think when you get too much material under the hood the rotor is trying to stir a near solid mass of clippings and it just can't do it. More HP could mean smoked belts, driveline failure, gearbox failure, etc. Several options, one is to go crazy slow. That gets old. The other is to mow higher and live with an ugly cut, then come back in a week or two and mow again when the clippings have deteriorated some. The other is to hit it with a rotary and then come back in a week or two and flail it.

I may have told this story, but we had a wet spring years ago and our church had 5' tall thick grass on some adjacent property. I took a 60 HP tractor with an 8' flail, and other guys showed up with much less impressive lower HP tractors with 60" rotary mowers. They worked circles around me. I had to go so slow, that I finally just loaded it all back on my trailer. I did go back later in the spring and gave it a nice buzz cut with the flail, but man in that super tall thick grass I had the wrong tool.

 

[troverman]

Yep, this makes sense. But overall, my point was that 21PTO horsepower was not getting it done on a 4-foot flail in thick grass over two feet tall...but applying 37PTO horsepower made all the difference. I think a 6-7 foot mower on a 26PTO horsepower is simply too much width. However, a 5-foot mower would likely be ideal.

 

[TerryCC]

To add to this topic, I recently mowed part of my cousin's property with my Caroni 1900. My tractor has 45 PTO hp. This was the first time it was mowed this year and some of the weeds were as high as my hood, most were as high as the front axle. I didn't have any difficulty until I got to a patch of a particular thick weed that had a matted tough stem. It didn't bog the tractor, but did smoke the belts. I lifted the mower and was immediately covered in weeds, the mower when lifted throws the weeds all over the tractor. It was the first time that I have had to mow in lowest gears. My experience makes the point that it isn't just the height of the weeds, but the thickness and toughness of the weeds that determines the speed and hp required. What is still impressive about a flail mower is the cut. All the mowed areas had a thin layer of ground up grass and weeds and not the bunched up mats of grass that my rotary mower leaves.

 

[IslandTractor]

Thought I would update on how the conversion from Caroni flails to FlailMaster flails went on my Caroni 1900. I disconnected the mower from the tractor and lifted it by the lower 3 point pins with my tractor's front end loader. The mower rolled over on its back and I used a jack stand on the upper 3 point mount to stabilize it, it was very stable and exposed the knives so that removal and replacement would be with me sitting on a stool rather than underneath.

I used an air ratchet and a box end wrench to remove the original bolts. A few nearly stalled the wrench, but the nuts all came off. I was prepared to cut them with a angle grinder if the air ratchet wouldn't remove them. This task too about 10 minutes.

I got the knives and clevises from FlailMaster, the same one detailed in this thread and the 2-3/4 x 3/8 grade 8 bolts and grade 8 nylock nuts from Nutty. Nutty has an intuitive website and you can order online, FailMaster you have to call. The knives came in two days, the nuts in 4 days. I was concerned looking at the FlailMaster clevises are 7/16 and the bolts are 3/8 but the "looseness" is perfect. It was a pleasant experience with FlailMaster and I received a thank you note a week later.

The bending and shaving of the clevises is the time thief. I bent and shaved the first clevis several times before getting it to fit. Using it as a template I bent the other 32 (5 are spares). To my surprise most didn't fit. The welded ears on the rotating drum have a noticeable difference in spacing. Using a dial caliper I discovered that 1.500 inches would work at every station, so I rebent and shaved all 33.

Reassembly went fast and took less than 10 minutes to reinstall knives and clevises to all stations. Because of the difference in the width of the ears at each station, some nuts have a single bolt thread exposed and some are flush and a few are about one thread short of being flush. However all were caught by the nylon lock in the nuts. If I lose a station, it will be probably because not enough contact with the nylon locking material and the bolt.

I picked up the mower with the front end loader by the top attachment point and it rolled back over. Connected it to the tractor and engaged the PTO and seemed to work fine with any noticeable vibration. Earlier I had one station missing, the clevis and knives at one end of the drum right at the bearing. The vibration was noticeable and the noise of the mower was also noticeable different.

Couple of questions for Island Tractor. When you are bending the clevises in the vice, do you bend until the ears touch before releasing the vice? I didn't and am concerned about how much material I removed from the clevis to get a 1.500 in overall width. Second question: Are all your clevis bolts either flush or extend slightly from the nylock nut? In the industry I worked in, all bolts had to extend one thread past the nut to be approved for use.

Great description of the conversion process.

Regarding your questions:

1) Yes, narrowing the 3/8" clevises is a time sink. I also use the try and fit then take a bit more off technique to get the clevises to fit. I didn't do all at once like you have. I just replaced any missing Caroni metric clevis with a new 3/8" so tended to modify a few at a time. My method uses a fairly big vice (Wilton ?5") and a cheater pipe. I put the ears in the vice just past the bolt hole and then crank down. Cannot recall the exact target measurement but 1.5," sounds about right. I don't crank until the ears touch but to maybe a 1/2" or ?5/8" gap remains. I try to compress/bend from the shoulder rather than the ears so that the holes stay lined up for the bolt. After compressing I then use a second vice outdoors (wood barn) to hold the clevis arms so I can use a grinder or flapdisk to remove material from the outside of each clevis arm. Then comes the trial fitting with a bolt to see if it swings freely. Almost always end up taking a bit more material off before putting the knives on and bolting.

2) Only a thread or less of bolt extends past the nylok nut. Never lost one. The less thread that protrudes the better. Much easier to remove the new shorter bolts than the banged up Caroni bolts.

3) I'd estimate our rocky soil claimed at least one clevis and knife set every 2-3 hours of mowing with the Caroni clevises before a clevis broke (losing the knives). In the past three years I haven't had a single 3/8" clevis break. I did lose one pair of knives when they broke (but the clevis survived and was reusable). I never had any knife break when using Caroni metric clevises so I think it's pretty clear that those clevises are the weak point (perhaps by design?).

4) I'm very happy with the modified 3/8" clevises from Flailmaster but I don't have a better more efficient way of doing the adaptation than what you described. The good news is that you only need to do it once.

Thanks again for documenting your process. I'm sure others will find it useful.