Flail mower noise

[Ricn]

Good Morning to all.
my Post concerns a Woodmaxx 60 inch flail mower bought new in 2017. So here goes my question.

Have the Woodmaxx 60 inch flail mower and to date has worked great, no issues so far I know of. So, my Son was here yesterday and in his opinion, my mower is quite noisy. He is basing this from his US Brand flail on his Kubota Trac Hoe telling me, "it makes much less noise than my Woodmaxx mower".

Not hearing flails before, I thought the noise from mine was normal but now I wonder if it has issues? Since new, maybe two years now, and having very, very low hours, (I keep records) and having kept it greased in recommended intervals, I'd appreciate opinions on noise levels to be expected on three point flail mowers, if that is at all possible. Also, I notice after mowing that the black drive side housing covering the belts is warm, not hot to the touch mind you, but definitely warm, is that normal?

When I ordered my unit, the sales guy told me they had just upgraded their bearings to much better ones, and my unit when shipped, would have these newer bearings.

Judging mower noise is not easy unless hearing several units and brands for comparison: around here though I know of none to compare to, so any opinions from the experts here on TBN would be great. I will say, this mower runs up to speed quickly and easily and when the tractor is at idle speed, and engaging the mower, it spins with ease. In mowing 8-12 inch high grass at pto speeds there is no bogging down of the mower or tractor telling me resistance may be low? My tractor is 25 hp diesel not working hard at all running this mower. I plan to remove the black housing, check the belts and tensioner both but as it has no slippage I can see when mowing then perhaps I have bearing issues?

Thanks for any ideas you may have concerning noise.

Ricn

 

[ericm979]

There's a lot of ways that different flails in perfect condition could make more or less noise. Blade shape and shape of the inside of the housing would affect the air and plant matter churning around inside. The shape and thickness of the housing will affect how much noise from that churning and from the bearings is transmitted to the listener outside. Of course if yours is a single wall housing and his is double wall that will make a difference too.

 

[Ricn]

Good points both. Mine is the single wall looks like with "Y" type blades for grass.

Ricn

 

[Billrog]

I have the same mower with about 30 to 40 hrs. on it makes noise but no more than the last one I had ( a Howard or Kabota ?). The gear box gets very warm and housings around the belts as well same as the last one I put hundreds of hrs. on keep 20 acres of light brush mowed twice a yr. for 25 yrs.

 

[audsp98]

Mowing video

Here's a video of mine. It's running at full RPM (540) and I don't think it's terribly loud.

 

[Granthol]

Noise between brands can vary. I wouldn't be too concerned if it works fine, has always worked fine, and sounds just like it always has.

 

[Ricn]

Billrog - Sounds like mine may be more normal then. Tried Audsp98 utube video but it would not run...Perhaps if taking the cover off and taking a look it will make me feel better if nothing else. No change in noise since new, good point there, Granthol.

Ricn

 

[leonz]

Hello Ricn,

If you have no broken side slicers or missing knife pairs it should sound just like a vacuum cleaner in short brush or good sod
and its just the issue of encountering brush as its sliced up and lifted over the flail mower rotor.

The other thing to keep in mind is the cutting height; the shorter the cutting height the more vacuum noise you will hear as the
flail mower shroud will be closer to the ground and the greater negative pressure gradient is created as the narrow height between the
ground and the shroud entrance is where all the air is entering.

The slower you travel forward the greater the vacuum sound will be as the side slicer knives will lift and clip more material more finely as you mow.

A forestry mulcher if that is what your son has is an different animal with a different type of flail assembly.

 

[Billrog]

Ricn don't look for trouble if there's a problem your going to hear it loud and clear , slipping belts will squeal , smoke and stink. a bearing going is going to squeal, hook the knife carring tube on something and bend it there'll be a lot of vibration ,and getting a stick or branch stuck in the knives a lot of rattling a banging. There's no grass guard on these so I make sure the grass that gets wound up on the ends of the shaft is removed with a bit of effort if left it can contribute to shortening the life of the bearings.

 

[Ricn]

Sure hope you guys are right about all this not being an issue but the Wife says the mower makes much more noise than when I bought it. Today, my Son came by again so we thought to investigate more. We started by removing the side cover over the belts then took all three belts off, so far so good, we then fired up the tractor just at idle speed an engaged the mower whereby everything sounded normal with no extra noise, of course only the driveline, gearbox and shaft were running with the drum and knives idle. We increased speed and all sounded normal to us so we reinstalled the belts and tensioner, adjusting belts to 3/8s play per manual then the outer cover. We ran it again and the noise is back as before, no change. We at least have proved the nasty noise its in the knife drum and or bearings as it only is there when the drum turns. My best description is, it sounds like a concrete truck with rocks only, no sand, concrete or water and turning much faster than concrete truck drums normally turn. Must be an awful noise to my neighbors down the road. While we had it apart, we grabbed the drum on each end shaking it hard to see if bearings etc, showed any looseness in them but all was tight. We applied more grease just to be sure but having greased the bearings yesterday, we were worried about over greasing them. As for my Sons flail on his trac-hoe, it is the same type as mine, a large round drum with knives, the only difference is, his mower is driven by hydraulic lines off the engine meaning no driveline. His mower makes a humming sound and very smooth when running wide open, more like the vacumn sound mentioned here..Our only thing now is to replace the drum bearings thinking them bad from new?

Ricn

Ricn

 

[leonz]

Hello and good morning Ricn,

First things first; you need to purchase a V belt tension guage from amazon or a gates V belt dealer. The amount of tension they are recommending for a three belt pulley system is too loose.

If your son has a mechanics stethoscope you can do this: when the tractor and mower are operating at the PTO speed of 540 RPM you can use the mechanics stethoscope to check for bearing noise. if there is any noise coming from the bearings it will be transmitted through the bearing housings and you will hear it and you need to call the seller and ask them what to do as it should not be doing this IF and only IF it does not sound like a vacuum cleaner when mowing at a 2 inch height with the belts tighter than they recommend.

If it sounds as if the mower sounds like a ready mix truck with granite aggregate with no water in it rolling around at idle its not healthy.

 

[Ricn]

Thanks Leonz for this feedback. Will work at these suggestions. The belts adjustment says 3/8's at 10lbs pressure so the gauge would be much more accurate than my fingers pushing on the belts for sure. I can get one of those from Amazon. We did notice, and when tightening the adjuster nut, that the three belts seemed to tighten unevenly, not a lot mind you, but a slight difference. The middle belt was the one we used for our final finger pressure test having the most tension of the three.

"So if the factory setting of 3/8 inch is to loose, what setting would be correct?"

Ricn

 

[leonz]

Hello Ricn,

OK, I will vent my spleen now GROWL HISSSS;


Its sounds exactly like they did not install three identical V belts with the same lot number and that is why you have the middle belt that is not tensioned.

If you are this far along I would check the ID numbers as they are the lot numbers.


If the name of the manufacturer is still visible and they have a web site you should be able to access their page that describes what they want to
see for the proper tension of the V belts.


A faster way would just go to the Gates Web site and look up their recommended belt tension recommendations.

You are stuck though; as the center belt is still too loose I would purchase 3 new V belts with identical lot numbers
as you will know that the webbing/thread used to reinforce the V belts came from the same lot number/spool.

A V belt that is loose will make a lot of noise so keep that in mind but you can still use the mower with the outer
and inner V belts for now if you remove the center V belt.

Its too bad that they did not use a triple web belt in the same size as you would not have the loose center V belt.

 

[Ricn]

The middle belt is tighter of the three, we set our tension using the middle belt.

 

[Billrog]

Ricn have you inspected the roller and knives thoroughly for a loose or bent knife hitting on the house or a small stick stuck stuck in there hitting on the housing because what you describing isn't a bearing or a belt noise. I've burned off belts, replaced bearings & the only thing that made a racket was wire , stick or a knife pulled loose. When I bent the drum holding the knives on my old flail I used it for a few more years but it vibrated and made a lot of noise.

 

[Ricn]

Billrog. Will be checking this for sure. Have done a quick glane already but something more is on my list, thaks!

 

[Ricn]

My flail mystery has been solved. My two Sons, bless their souls, came by today for supper. Now, if having boys yourselves, you all know how they love their Mothers cooking, so after their second helping and with cake afterwards they went to the barn listening to the flail noise where upon they tore it all down in maybe 45 minutes and wow, the drive side bearing is toast! on a brand new Woodmaxx with 6 hours maybe, just maybe of use and with NSK bearings. So the story continues but with the youngest taking both ends to his shop where he will replace bearings and seals with new and reinstall everything next weekend. At our age these boys are such a blessing but they always have been; we always give praise to God for them. - Thanks again for all the pointers and answers, never to old to learn.

Will post again when it's all running again!

Ricn

 

[Billrog]

:thumbsup:

 

[leonz]

Hello Ricn,

I am unable to sleep and I am glad I have visited the forum. I am sorry to hear that you lost the bearings.
Six hours for a bearing to go bad is too short a life span.

It would be great if your boys could describe what they found and whether the inner race on the drive side was spinning and not locked in place.
They should have no trouble finding bearings and seals for the flail mower, The national oil seal companies seal are still available as far as I know.
SKF, Timken, and Sealmaster roller bearings are still available as well and the seals and bearings will all match up as all bearings are metric.


leonz

 

[Ricn]

I believe the inners are tight. My Son took the necessary parts home saying, they must be pressed out and back in. They are taking care of all this for me and will be out next weekend to get things all together and running correctly, a blessing for sure! I will seek the answers to your questions when they come and let you know what they say. - The drive bearing was a mess, little balls and metal fragments all clustered up in a gooey ball. The other end is fine but they are replacing everything on both ends. This mower has NSK bearings that I'm told are good but my Son is getting another brand I believe, something he uses lots of in his gravel crushing business. It is his opinion this was caused by my over greasing but could also be a defective bearing as well, to hard to tell but I had way to much grease in both bearings evidently. He went on to say that, three years ago he had a bearing rep come out due to all their equipment bearing failures. This resulted in having employees grease bearings from a chart provided by the bearing manufacturer based on rpm and hours of run time, and with the correct amount of grease pumped in for each bearing application. This program has dropped failure rate by some 75% on machinery that runs 12 hour days.
Ricn