Flail Mower Let's talk flail mowers

[IslandTractor]

Having busted several clevises on my Caroni 1900 recently during an initial lot clearing, I discovered the sticker shock of buying parts from Agri Supply for this implement. Querying here for options resulted in the sad news known to many of you - nobody seems to have found an alternative for the ridiculously priced $7 metric clevis. That didn't sit well with me...

I may have found a solution. I say "may", as I've not actually tried it yet - but once I've used up the last of my four spare metric clevises from Agri Supply, I'll give it a try and report back if nobody else has given it a whirl.

I got the idea from Island Tractor's post, wherein he gave the info on cheaper blades from Flailmaster.com. I picked up a bunch of those, and they do indeed work fine. However, he also mentioned an SAE clevis - Flailmaster part #M-100761. This clevis is too wide to fit between the ears of the Caroni drum. However...I was able to easily tweak it to fit. Pic:

I simply took one of the M10x80mm bolts and a nut, and pressed the SAE clevis together. It deformed as I expected, such that the ears are no longer perfectly parallel - but that doesn't seem to matter. The assembly shown above still moves easily on the stock M10x80mm bolt, swinging back and forth with no interference. The clevis modification takes all of a minute or so.

Some caveats:

- You'll likely want to replace all of your metric clevises if you go this route - not just the broken ones. This SAE clevis is indeed beefier than the metric one, and weighs more. I'd be concerned about proper balance mixing them up.

- The entire assembly is just a tad longer than stock - perhaps 1/8".

Here's a breakdown of current pricing from Agri Supply vs. the sources I used for the entire assembly:

Agri Supply

Clevis: 6.99
2 x Blades@ 3.49: 6.98
M10x80mm Bolt: 3.49
M10 Nylock nut: 1.49
Total: $18.95

Elsewhere

Clevis M-100761: $2.80 (flailmaster.com)
2 x M-108381 blades@$1.54: 3.08 (flailmaster.com)
M10x80mm Bolt: 0.46 (nutty.com)
M10 Nylock nut: 0.13 (nutty.com)
Total: $6.47

Yup...almost 1/3 the price. And, based on the sturdier appearance of the SAE clevis - my guess is, the cheaper assembly will hold up to more abuse.

Again - untested, but looks promising.

I was looking to get an update from DaNag about his experiences over the past two seasons using the Flailmaster clevis instead of the original Caroni clevis. He doesn't seem to be very active on TBN these days so we may not hear back. I decided to go ahead and start using the Flailmaster clevises using DaNag's modification technique which is simply to squeeze the open end of the clevis in a table vise (using a pipe for leverage) and then using a grinder or flap disk to shave off a small amount extra (he did 1/6", I did probably only 1/16") so the clevis swings freely in the mount. I'm posting this to give you my experience after starting to switch over.

As you Caroni owners undoubtedly know, the original Caroni supplied clevises wear out pretty quickly (a season or two) and when they break, you lose the clevis plus a couple of knives. PITA and expensive as each set (clevis, knives and bolt/nut) costs almost $20 from AgriSupply. I did some aggressive mowing this week and had to replace seven sets. Over the seven years I have had my mower, I have probably replaced about 40-50 sets. That starts to add up even if using the cheaper Flailmaster blades and purchasing the M10x80mm bolt and lock nut in bulk. Also, as the mower gets out of balance after losing a set or two, it means frequently having to stop, return to the barn and spend twenty minutes changing out the broken sets. As I stated, a PITA and a blemish on what is otherwise a very fine mower. The issue is pretty clearly that the Caroni supplied clevises simply wear down pretty quickly and once they get to about 1/4" thickness, they break when hitting something fairly solid such as a stump or rock. See photo #1 which shows that virtually every single break is at the corner of the clevis and that the clevises are worn by about half (don't have any remaining new Caroni clevises to compare in the photo but they start off about 3/8" thick). When new they don't break nearly as easily. After a season or two the clevises become fragile.

I ordered a full set of 28 Flailmaster clevises plus spares (part number M-100761 from flailmaster.com) as well as a new set of blades. I used the vice to squeeze the clevis to an OD of 1.5" and then grinder to remove maybe a 1/32 from each side. See photos 2 and 3. I started with the intention of switching over the whole set at once just as DaNag had done. However, after modifying a few of the new Flailmaster clevises and mounting them with blades, I decided to see how the mower ran. Smooth. No evidence of imbalance even though the Flailmaster clevis is about 0.8 ounces heavier than the Caroni version. After that little test I decided to do some light mowing with the mixed set. Worked fine. Then moved to heavier mowing (basically fields unmown in two years with waist high grass and brush and ???occasional rocks and unseen stumps/tree limbs etc. Mowing in this heavier duty test went fine but I noticed after a while some increased vibration so I checked the mower and sure enough I had lost another three Caroni clevis sets. Back to barn, put in three more Flailmasters and went mowing again. All well but again after a while vibration and to no surprise a few more Caroni sets were gone. At this point I just decided that I will bring sets of the modified Flailmaster parts into the field with me and change them out as needed. There does NOT seem to be any reason to bother changing out all 28 sets at once (it can be a challenge to unbolt some of the old ones as the outboard threads on the M10 bolts are pretty banged up after years of mowing).

Bottom line:
1) DaNag's modification (squeeze in vice plus grinder to the sides) works just fine.
2) The Flailmaster clevises are heavier duty
3) No need to change out all 28 at once as the rotor is still in balance if only one or two at a time are changed.

Photos 2 and 3 show modified clevis (actually I ground a bit more off after taking photo). Photo 4 shows simply the field I was mowing.

 

[bruceha2000]

I was looking to get an update from DaNag about his experiences over the past two seasons using the Flailmaster clevis instead of the original Caroni clevis. He doesn't seem to be very active on TBN these days so we may not hear back. I decided to go ahead and start using the Flailmaster clevises using DaNag's modification technique which is simply to squeeze the open end of the clevis in a table vise (using a pipe for leverage) and then using a grinder or flap disk to shave off a small amount extra (he did 1/6", I did probably only 1/16") so the clevis swings freely in the mount. I'm posting this to give you my experience after starting to switch over.

As you Caroni owners undoubtedly know, the original Caroni supplied clevises wear out pretty quickly (a season or two) and when they break, you lose the clevis plus a couple of knives. PITA and expensive as each set (clevis, knives and bolt/nut) costs almost $20 from AgriSupply. I did some aggressive mowing this week and had to replace seven sets. Over the seven years I have had my mower, I have probably replaced about 40-50 sets. That starts to add up even if using the cheaper Flailmaster blades and purchasing the M10x80mm bolt and lock nut in bulk. Also, as the mower gets out of balance after losing a set or two, it means frequently having to stop, return to the barn and spend twenty minutes changing out the broken sets. As I stated, a PITA and a blemish on what is otherwise a very fine mower. The issue is pretty clearly that the Caroni supplied clevises simply wear down pretty quickly and once they get to about 1/4" thickness, they break when hitting something fairly solid such as a stump or rock. See photo #1 which shows that virtually every single break is at the corner of the clevis and that the clevises are worn by about half (don't have any remaining new Caroni clevises to compare in the photo but they start off about 3/8" thick). When new they don't break nearly as easily. After a season or two the clevises become fragile.

I ordered a full set of 28 Flailmaster clevises plus spares (part number M-100761 from flailmaster.com) as well as a new set of blades. I used the vice to squeeze the clevis to an OD of 1.5" and then grinder to remove maybe a 1/32 from each side. See photos 2 and 3. I started with the intention of switching over the whole set at once just as DaNag had done. However, after modifying a few of the new Flailmaster clevises and mounting them with blades, I decided to see how the mower ran. Smooth. No evidence of imbalance even though the Flailmaster clevis is about 0.8 ounces heavier than the Caroni version. After that little test I decided to do some light mowing with the mixed set. Worked fine. Then moved to heavier mowing (basically fields unmown in two years with waist high grass and brush and ???occasional rocks and unseen stumps/tree limbs etc. Mowing in this heavier duty test went fine but I noticed after a while some increased vibration so I checked the mower and sure enough I had lost another three Caroni clevis sets. Back to barn, put in three more Flailmasters and went mowing again. All well but again after a while vibration and to no surprise a few more Caroni sets were gone. At this point I just decided that I will bring sets of the modified Flailmaster parts into the field with me and change them out as needed. There does NOT seem to be any reason to bother changing out all 28 sets at once (it can be a challenge to unbolt some of the old ones as the outboard threads on the M10 bolts are pretty banged up after years of mowing).

Bottom line:
1) DaNag's modification (squeeze in vice plus grinder to the sides) works just fine.
2) The Flailmaster clevises are heavier duty
3) No need to change out all 28 at once as the rotor is still in balance if only one or two at a time are changed.

Photos 2 and 3 show modified clevis (actually I ground a bit more off after taking photo). Photo 4 shows simply the field I was mowing.

Double post! Second one with the missing photo 4

Geez, you've spent over half the cost (today! probably way more than yours cost 7 years ago) of a new 73" mower just replacing knives and clevises!

OK, I still don't have a flail but that is OK because the biggest tractor I have is a Craftsman garden tractor But I have what is probably a stupid question:
Seems a waste having those OEM Caroni knives spread all over the field. If they are going to go flying every time the OEM clevis snaps, can you just get the Flailmaster clevises, replace all the worn and about to snap OEM clevises at once using the OEM, not lost YET, knives? My GUESS as to the answer is "no, the hole in the knife is too small for the new clevis".

 

[IslandTractor]

Double post! Second one with the missing photo 4

Geez, you've spent over half the cost (today! probably way more than yours cost 7 years ago) of a new 73" mower just replacing knives and clevises!

OK, I still don't have a flail but that is OK because the biggest tractor I have is a Craftsman garden tractor But I have what is probably a stupid question:
Seems a waste having those OEM Caroni knives spread all over the field. If they are going to go flying every time the OEM clevis snaps, can you just get the Flailmaster clevises, replace all the worn and about to snap OEM clevises at once using the OEM, not lost YET, knives? My GUESS as to the answer is "no, the hole in the knife is too small for the new clevis".

1) Yeah, I retyped the whole darn post after my ipad told me that the "post failed"! Bummer. I was on the island and posts frequently do fail. I usually copy it before posting just in case as it cannot be recovered. This time I forgot to and when I couldn't find the post I ended up retyping the whole thing. Another 20 minutes of life lost!!!

2) The maintenance costs of the Caroni is not trivial, at least for someone who routinely hits hidden rocks, old farm equipment and stumps which tend to break the older Caroni clevises resulting in loss of knives and clevis. It is really the clevis that is the expense as Flailmaster knives fit the Caroni clevis so I stopped using AgriSupply as a source of knives and bolts long ago. Still, I have never had to resharpen or replace worn out knives as they are lost frequently enough that there aren't any seven year old ones left anymore anyway. As noted by both DaNag and myself, it is the Caroni metric clevis that is the weak point. I may end up getting organized and just replacing all the remaining ones before they break but the cost of the Flailmaster blades is cheap enough (about $3-4 for a pair) that I'd probably just replace the old ones anyway. Mostly the reason I just started mowing with a mixed set of Flailmaster and Caroni clevises was because I was 1) bored at the thought of replacing 28 sets all at once, 2) I really needed to mow while the weather was good and 3) I was pissed off at my HF air ratchet wrench which didn't have the guts (claimed only 45lb/ft torque but not sure it was even that much) to remove the old bolts which meant that I had to spend about five minutes per set manually wrenching while crouched behind and partly underneath the mower. The idea of 5 minutes times 28 changing out knives/clevises was not appealing. My attention deficit disorder kicked in so I just went mowing.

Added photos of pre and mid mowing of field.

 

[bruceha2000]

1) Yeah, I retyped the whole darn post after my ipad told me that the "post failed"! Bummer. I was on the island and posts frequently do fail. I usually copy it before posting just in case as it cannot be recovered. This time I forgot to and when I couldn't find the post I ended up retyping the whole thing. Another 20 minutes of life lost!!!

2) The maintenance costs of the Caroni is not trivial, at least for someone who routinely hits hidden rocks, old farm equipment and stumps which tend to break the older Caroni clevises resulting in loss of knives and clevis. It is really the clevis that is the expense as Flailmaster knives fit the Caroni clevis so I stopped using AgriSupply as a source of knives and bolts long ago. Still, I have never had to resharpen or replace worn out knives as they are lost frequently enough that there aren't any seven year old ones left anymore anyway. As noted by both DaNag and myself, it is the Caroni metric clevis that is the weak point. I may end up getting organized and just replacing all the remaining ones before they break but the cost of the Flailmaster blades is cheap enough (about $3-4 for a pair) that I'd probably just replace the old ones anyway. Mostly the reason I just started mowing with a mixed set of Flailmaster and Caroni clevises was because I was 1) bored at the thought of replacing 28 sets all at once, 2) I really needed to mow while the weather was good and 3) I was pissed off at my HF air ratchet wrench which didn't have the guts (claimed only 45lb/ft torque but not sure it was even that much) to remove the old bolts which meant that I had to spend about five minutes per set manually wrenching while crouched behind and partly underneath the mower. The idea of 5 minutes times 28 changing out knives/clevises was not appealing. My attention deficit disorder kicked in so I just went mowing.

Added photos of pre and mid mowing of field.

Looks like it does a nice job. Sooo, WOULD the OEM Caroni knives fit the Flailmaster clevis? I've never sharpened a flail knife so I have no idea how much work that is vs buying new Flailmaster knives. I can understand not wanting to spend 2.5 hours replacing them all at once. Of course, if the Flailmaster clevises don't break, I guess at some point you have to spend all that time to take them off and then sharpen them. Darned that good quality product! Guess it is a winter project, presuming you take them off the flail before it gets too cold.

I can say I've spent WAY too much time sharpening the 3 blades on my 54" deck after mowing the 4 acres of field in 6 sections originally filled with 4' tall weeds/grass that I had paid a guy from up the road to whack with his 6' sickle mower and 40 hp compact. Lots of rocks to hit with a deck that won't raise up more than 4" off the ground. And of course all that tall stuff just laid down so no way to see what is hidden underneath prior to "first pass". I've pretty much found them all (I HOPE!), plus, sadly, some hot wire that wound its way above one of the blades and into the "cup" of the shaft assembly and messing up the "star" on the other 2. Managed to use the dremel to reshape the star parts. And of course, on a second mowing while I was CAREFULLY avoiding a rock on the left I could now see, I managed to whack one to the right that I had not hit before. Must have had a wheel just a bit in a low spot. I sure wish the people that owned this place 100 years ago had had a fetish for dynamite WAY too much ledge and big rocks I can't get out without a backhoe. I marked a bunch with old ski poles "generously" left behind in the barn by the prior owners but I ran out of poles WAY before I ran out of rocks. Need to get some cheap marker poles.

 

[IslandTractor]

Yes, the Caroni knives and Flailmaster knives fit on both types of clevises. As I noted, because the Caroni clevises break and lose the used knives, I've never had to sharpen them. I believe the knives are tempered steel so it is important not to simply grind them hot if temper is to be maintained. But honestly I've just never gotten to the point of trying to figure out what to do. If the Flailmaster clevises last a lot longer then I may need to learn to sharpen the knives. Question of whether to take them off or sharpen in place will depend on how difficult it is to remove the nut and bolt. Also, they are double sided so just reversing them the first time would be adequate. Some are quite difficult to remove as the threads get pretty mangled after a few years of flail mowing. Might be easier to sharpen in place.

You live in Vermont. I'm sure you have more than just big ledges of rock. I've got the big ledges pretty well memorized and usually leave a bit of tall grass near them alone so I can identify them again. I think everyone in New England has yearly crops of rocks that come up each spring after a few freeze thaw cycles. The new smaller rocks still are a problem with first mowing in the spring.

 

[DavesTractor]

Regarding flail mowers vs flail shredders, we can run a foot of flail mower with 4 PTO HP in typical orchard situations. With a true shredder with big hammers, a foot takes about 10 PTO HP. I mow my orchard with a 10' Vrisimo with a 45 PTO HP tractor and it does fine. Grunts a little if I let it get too tall. But if I were shredding, I'd have to stay at about 5' width with this same tractor.

If you are mowing hood high stuff, my 4 HP/foot rule gets thrown out the window. If I have to mow something that tall, I do it with a rotary first and then come back later and flail it to give it a more finished look.

BTW, USA made scoop type flail knifes for a Vrisimo mower are about $2.25 each and you only use one per hanger. And you can change out all of the knives on a 10' mower in well under and hour. After 2 or 3 knife changes, sometimes you have to swap out the d-rings, which are also a couple of bucks. These are expensive mowers to purchase, but not expensive to operate.

 

[IslandTractor]

I assume the Vrismo has some sort of hanger pin that slides out rather than having to be individually unbolted. Perhaps effective air tools would also speed things up but I find the unbolting of the individual clevis sets to be pretty time consuming. Uncomfortable work position makes the time seem longer too. Consumer grade air ratchets don't have the guts to unbolt the locknuts over damaged threads so there is a fair amount of grunt work involved. I'd love to have a Vrismo or Alamo etc but as I can purchase about three or four of the Caroni's for that price, I'll make do.

I use low range and about slow granny walking speed when mowing through hood high weeds/grasses. I run the engine at PTO speed (2500 rpm with PTO engaged and unloaded mower running) and find the RPMs hover about 2200 while actually mowing. I stall occasionally but almost always because I ran over a bump of earth that the mower tried to mow. Sometimes a piece of firewood etc. The engine obviously pulls down when mowing over a sapling or two also.

When just mowing knee high grass I typically run at about 2200rpm unloaded and at a moderate walking speed. No issues with pull down unless I hit a particularly lush stand of grasses.

 

[DavesTractor]

Island, yes Vrisimo has two styles. Neither of which require unbolting a clevis. One is where you pull a rod and all the flails in a row drop to the ground. The other style is a cleverly designed d-ring setup where you just twist the knife/ring a certain way and it comes off. I understand the price difference, these certainly aren't for everyone. They make more sense if you mow hours every day. A typical Vrisimo buyer in an orchard around here will mow the equivalent of hundreds of acres each season. If they have 120 acres and mow every three weeks for a 6 month season, that is 960 acres of mowing.

Vrisimo has just come out with a less expensive line. A 60" can now be bought for about $3995, about $1000 cheaper and it is still made in California and top quality. They just lightened it up a little. That is still probably double what an import mower costs though. But considering knife changes are much cheaper and faster, that narrows the gap a little. And they take standard bearings, not special double row metric units that can be pricey. In the long run, if you mow a lot the better mower becomes cheaper. But if you just do a few acres now and then, the cheaper mower is not a bad way to go. I'm not trying to convince anyone otherwise, this is just for discussion.

 

[IslandTractor]

You don't need to convince me that Vrisimo mowers are top notch. However, assuming the Flailmaster clevises and knives last 4-5 years of mowing (maybe 150-200 acres in my case) it would take about thirty or forty years to make up the double cost over the Caroni.

I still think the Caroni is a great deal for private or light Ag use. If I had to do it again, I'd buy the same TM1900 for $1900 but immediately change out the clevises to Flailmaster before using it and sell the Caroni clevises at a good discount to someone else as spares. That would easily pay for the Flailmaster clevises and as the nuts and bolts would be unused it would be a simple and much faster task to change out all 28 sets. That and I would immediately put on a set of Gates kevlar belts and keep the Caroni supplied belts as emergency spares.

 

[DavesTractor]

The Caroni is a lot of mower for the $$, no doubt. If you can get 4-5 years out of knives/clevises, then the cost is no big deal really. If you had to replace them each season it may be a little different.