Flail Mower Let's talk flail mowers

[CADplans]

I am sorry to hear about you guys that have to work on your flail mowers,,,

On another note,
I got to run my 390 yesterday, mowing about 3 acres of pasture, into a lawn-like finish

I like to mow this time of the year, before the annuals like milkweed go to seed.

I have to be careful, a neighbor has some deteriorated high tensile fence.
Three times I have wound up 30-40 feet of that wire, always at the end of the rotor.

Thankfully, I have an oxy-acetylene torch,,, I do not have a cutter that will cut that wire,,,

 

[Steave]

Ozarks Landowner my mower (Mott 72) vibrates the mower, tractor, and me until it reaches close to PTO speed and gets all the knives slinging outward then it smoothes out nicely. When I'm mowing I have my ear protection on and tunes going but if I hit a thick patch of grass and the mower slows it will vibrate slightly and I know to raise the 3ph before I even look back to see what happened. Then it's slow down until I get out of the thicker stuff.

I'm not sure (Maybe a pro can verify) but I think most flail mowers are designed to run very close to PTO speed. Actually its about the only time I run my tractor at that speed. So when you're trying it make sure you're at the correct speed. If you have all the knives removed you shouldn't feel much if any vibration no matter what speed you run it.

Look at the bright side if you can't keep it from vibrating mount you a chair on the dang thing. :thumbsup:

 

[CADplans]

I think most flail mowers are designed to run very close to PTO speed. Actually its about the only time I run my tractor at that speed. So when you're trying it make sure you're at the correct speed. If you have all the knives removed you shouldn't feel much if any vibration no matter what speed you run it.

Look at the bright side if you can't keep it from vibrating mount you a chair on the dang thing. :thumbsup:

My JD 390 runs smooth at any speed, even at an idle.

Maybe my rotor is heavy compared to the weight of the knives??

When I engage the pto, even at an idle, there is only a small "woosh" sound of the blades spinning
and the mower itself will "torque twist" if the mower is off the ground.

It is smooth,,,,,

 

[IslandTractor]

My Caroni runs more smoothly at some RPM compared to others. I can tell when I've lost a set of knives pretty easily by change in vibration..Losing one set is sometimes hard to notice immediately but losing two is very noticeable.

 

[Steave]

My JD 390 runs smooth at any speed, even at an idle.

Maybe my rotor is heavy compared to the weight of the knives??

When I engage the pto, even at an idle, there is only a small "woosh" sound of the blades spinning
and the mower itself will "torque twist" if the mower is off the ground.

It is smooth,,,,,

Yea your JD 390 is heavier. 90.5" cutting width and mine is 72". It wouldn't have to be the JD but I'd like to have one with about a 2' offset. That would be so handy.

Mine jumps and carries on until the knives get going and when I shut it down it does it again at a certain rpm. It does have a few more knives than the JD390 but I wouldn't think that's the reason. I would lean toward the weight difference. The Mott weighs 530 lbs with the finish cut knives. It has 92 stations with 184 knives. The JD390 has 84 stations with 168 knives. Not sure how much the JD weights but would guess 900 + ??

 

[Permaculturist]

I got my new Berti TA/S 220 running today for the first time. This picture shows where I began mowing. I cut about 1.5km of ditch in under 2hrs and didn't break anything. The road looks amazing now, but you'll have to take my word for it, cause I forgot to take the 'after' pictures. Now I have quite a bit of work to do with the thinning saw and chainsaw so I can make room for the tractor on the other side of the ditches. Even though I can fit, it's too wet and I'm too heavy to drive down the bottom of the ditch cutting up the other bank. That job will have to wait for the leaves (and the temps) to drop.

I have a bunch more work to do with this Berti, and I'll make sure I film some of it.

 

[CADplans]

Yea your JD 390 is heavier. 90.5" cutting width and mine is 72". The JD390 has 84 stations with 168 knives. Not sure how much the JD weights but would guess 900 + ??

The 390 weighs about 1,200 pounds,,,

 

[Steave]

The 390 weighs about 1,200 pounds,,,

Hey I got the + right. :thumbsup: That would explain the smooth running, the heavier the better. That would be a little more than I would want to drag around though. I thought my Mott was heavy at 530 lbs. I've heard folks say they weigh 800 lbs some say 900 lbs but I weighed mine with my overhead hoist scale and it said 530 lbs I don't think the scales are too far off ??

Does your JD cut good at slow rpms or do you run it at higher rpms. I wish mine had a 6:1 ratio gearbox so I could run at a lower engine speed. My ford reaches PTO speed at 1800 engine speed but I like to run it about 1600. The gearbox on the Mott is 4:1 ratio so the rotor is turning at 2160 rpm.

 

[Steave]

My Caroni runs more smoothly at some RPM compared to others. I can tell when I've lost a set of knives pretty easily by change in vibration..Losing one set is sometimes hard to notice immediately but losing two is very noticeable.

I better knock on wood but miraculously haven't lost any knives yet. Pretty sure I'd be able to feel it if and when I do. I removed the outer sets of knives as they're extremely close to the side plates and you can see where they have rubbed before. I saved those for spares, sure hope I Never need them.

IslandTractor I appreciate all the information you've given on this thread. It's helped me learn how to use and maintain my mower. I haven't had it long but I've used it enough to know it's a keeper.:thumbsup:

 

[CADplans]

Hey I got the + right. :thumbsup: That would explain the smooth running, the heavier the better. That would be a little more than I would want to drag around though. I thought my Mott was heavy at 530 lbs. I've heard folks say they weigh 800 lbs some say 900 lbs but I weighed mine with my overhead hoist scale and it said 530 lbs I don't think the scales are too far off ??

Does your JD cut good at slow rpms or do you run it at higher rpms.

I see very little difference cutting at pto speed, or half that,,,
in grass under 2 feet tall.

I usually slow way down in turns, the 390 keeps cutting nicely.

In 3 feet plus tall grass,,, the 390 only cuts nice at full pto speed.
If I try to cut at lower pto speed, the tall grass will make the 390 chatter.