Problems using our flail mower.

[ukjim]

Hi everyone, newbie here from the UK.

We have approx 5 acres of field, with a small orchard (less than half and acre in the middle).

We have a kubota 7100 tractor with a flail mower attachment.

The problem we are having is that the flail mower seems to just flatten the grass not cut it. Thw tractor does have wide turf tyres on which flattens the grass down a bit as you go over it/before the mower gets to it - would this be an issue?

It rips up a little bit of grass but not much. We are using it in high/normal range, 1st gear, and the pto in the slowest setting (1).

All that happens is it rolls the majority of the grass flat and rips up a few strands. We want a close cut.

The grass is approx 6"-12" tall, with a few weeds but not many.

The flail mower is "well used" and fairly rusty. Would we be better with a finishing mower/topper or just a new flail mower - or are we using it wrongly.

Thanks for your time.
Jim

 

[TripleR]

If he doesn't respond, check with leonz as he knows all about flail mowers. He has been very helpful to me on different subjects.

 

[stravis]

Sometimes in really thick grass with my John Deere 25a flail, the belt will start to slip and all it does is lay the grass down. You might check to make sure the belt is tight.

You mention that you have the pto in the slowest setting, looking your tractor up on tractor data, I see it has three settings. 514, 786, and 1498. What type of flail are you using? You need to make sure that the rated speed for the gearbox is the speed you're using on your pto setting. If you're turning the pto at a lower speed than the flail is designed for, it certainly won't cut as well.

Last thing I can think of is knives. What kind of knives are you using and what shape are they in? Are any missing?

 

[stravis]

If your tractor is the one I found on tractor data, you have 13 pto horse power. I don't know of any flails (there could be several, I just don't know of any) that will work well with only 13 pto horse power. That could be your problem as well. If you tell us what kind of flail you're using, we can look up the required horsepower for it.

 

[gwdixon]

We are using it in high/normal range, 1st gear, and the pto in the slowest setting (1).

Jim

To cut with a flail mower correctly the knives have to be spinning rapidly. It should cut 6" grass with no problems even if the knives are dull.

 

[ukjim]

Thanks for the quick responses guys.

The flail came as a bit of an extra with the tractor (we bought it for the front loader/to pull a trailer) and the flail was thrown in for not much extra. I dont know the make its very old/rusty but had had new bearings/belt when we bought it. It dosn't really owe us anything so if it needs replacing = so be it, but it would be nice to get it working if possible.

Unfortunately that's not much help is it :laughing: - I dont know the make, or the speed setting it should be on.

The seller we originally bought it off said the slowest speed setting would be best, but I'll be honest it does look like its turning quite slowly. I did try it in the 2nd speed setting and after 50m or so the belt was getting a little smokey so it obviously wasnt happy with that speed.

Your correct, I think the PTO power is approx 13hp - it may be that that just isn't enough for a flail? Would it be enough for any other kind of mower or is it just not cut out for mowing?

It actually seems to work better in rough grass/nettles/brambles/thorns - because it shreds more than flattens them - but on grass (long or short) it barely cuts anything at all.

there's 2 blades/knives missing but that's all. The rest arnt particularly sharp, but I didnt want to buy a new set if there was something else wrong, or the tractor just couldnt do the job in the first place?

Thanks again
Jim

 

[gwdixon]

I did try it in the 2nd speed setting and after 50m or so the belt was getting a little smokey so it obviously wasnt happy with that speed.

Thanks again
Jim

The additional information is a help.

You don't seem to be particularly attached to the mower and since it has new bearings and a new belt my tendency would be to run it at high speed and whatever happens, happens.

The knives should be rotating so fast that they are a blur and cannot be individually distinguished.

It will make noise but the new bearings and belt should be able to handle it.

Maybe the smoking belt was due to its newness. One thing to check is to take off the belt, or loosen it, and see if the all of the pulleys and the main shaft turn easily by hand before proceeding to run it at high speed.

 

[flusher]

Hi everyone, newbie here from the UK.

We have approx 5 acres of field, with a small orchard (less than half and acre in the middle).

We have a kubota 7100 tractor with a flail mower attachment.

The problem we are having is that the flail mower seems to just flatten the grass not cut it. Thw tractor does have wide turf tyres on which flattens the grass down a bit as you go over it/before the mower gets to it - would this be an issue?

It rips up a little bit of grass but not much. We are using it in high/normal range, 1st gear, and the pto in the slowest setting (1).

All that happens is it rolls the majority of the grass flat and rips up a few strands. We want a close cut.

The grass is approx 6"-12" tall, with a few weeds but not many.

The flail mower is "well used" and fairly rusty. Would we be better with a finishing mower/topper or just a new flail mower - or are we using it wrongly.

Thanks for your time.
Jim

The rule of thumb is 5hp (pto) per foot of flail mower width. You might get by with a little less in thin grass/weeds, but that 7100 seems to be marginal on pto hp.

 

[CharlieS]

Even with limited horsepower available, IF the mower's operating correctly, in an overworking condition, to much load should lug the tractor down, not cause the mower to just flatten the grass, as long as the mower is height adjusted properly.
To quote the OP, " I did try it in the 2nd speed setting and after 50m or so the belt was getting a little smokey so it obviously wasnt happy with that speed" which tells me quite probably a belt issue. Loose, or excessivly worn belt.
If it was a frozen bearing, the belt would slip/smoke almost immediately no matter what pto speed.
I'd suggest checking the belt for excessive wear and be sure its tensioned properly.
The indicated low speed on the pto (514 rpm's) is close enough to the U.S. standard 540 that even though blade speed may be a bit slow by our standards, some cutting should occur. Most likely it all comes back to a drive belt issue.

 

[stravis]

I think the 13 hp is probably not quite enough, but it's worth trying. I'd be willing to bet that the belt was smoking because it was slipping on the pulley. It would do that if it was loose. I'd tighten the belt up and try mowing with the pto on the 2nd speed. If the tractor isn't powerful enough, you'll know it. The tractor engine will be bogging down. If it doesn't and the mower cuts well, you're good to go. Just make sure to keep the bearings all greased up.

As for replacement mowers, most 4' rotary mowers (brush hogs) that I can find require at least 18 pto hp. I don't know if they make them smaller than that. I found a 4' Frontier finish mower that only required 16. You might be able to find something that you could pull. One option might be the finish mowers that you pull behind an ATV that have their own on board power. You could pull that behind your tractor. FYI, the smallest flail that JD makes is 4'-10" and requires a minimum of 30 PTO hp.

If I were in your situation, I'd keep the tractor for front loader and to pull a trailer like you originally bought it for and I'd get a good fast zero turn riding mower like a Hustler, Dixie Chopper, etc. (I don't know what y'all have available over there) for the mowing. A Dixie Chopper could cut a well groomed flat 5 acres very quickly, actually faster than your tractor with a rotary mower.