Flail Mower Let's talk flail mowers

[Gator6x4]

My guess is that the flail is being stressed to the point of the flails being stopped and the Tractor PTO is still turning and the Flail drive pulley is spinning causing belt wear, belt tracking off the pulley or jumping off the pulley and finally belt breakage.

 

[leonz]

Hello and good afternoon Quarryscapes,

I want to welcome you as the newest resident member of the flail mower nations from Great Britain.

The conditions/operating measures you describe are well defined and tell me that you have been mowing
too fast for conditions and have worn hammer knives and you need side slicer knives.

About your beautiful flail mower, you need to slow down and change the hammer knives to side slicer knives
to deal with your mowing conditions.

Please believe me when I explain to you in great detail how to overcome this issue as I have owned and used
flail mowers for over 4 decades here on this side of the pond.l

I have to leave right now but I will come back to this later. I want you to visit your stockist and purchase a
complete set of side slicer knives and new V belts-preferably kevlar reinforced V belts from an auto parts store
and get back to me as I want to help you with this as you have a forever mower that will outlive every tractor
you put it on.

I also want you to purchase a V belt tension gauge to help with your V belts life span.

I have to go

 

[dadohead]

I see often mentioning of V-belt tension gauge which makes me wonder why are the manufacturers not using spring loaded tensioner, like shown in my old Ford 917L Special below - perhaps it's just cheaper to make them without one?

Yes! Cost. Retired tractor engineer here. You typically see sprung tensioners on high quality drives that see variable loading. Why? The belt tension is held to a low constant regardless of the loading allowing long life for the drive.

Many belt manufacturers advise their V-belts run to a 5:1 tension ratio (although ratios as low as 10:1 run fine without slippage).

Here is a typical drive with 5:1 tension ratio at full load. Wonderful. Look what happens to tensions when the loading is lightened or the drive stops:

Now add a backside sprung idler tensioned for full load.

Same result right? Now analyze at low or no load:

Huge difference... belt tension lowered by 1/3!

If a drive only see's constant loading (air compressor for example) a sprung idler doesn't offer much advantage. If a drive will see variable loading (like mowers).... a sprung idler lowers tensions considerably and increases life on belts, sheaves, and bearings. Adds cost though. Hope this helps!

 

[leonz]

Yes! Cost. Retired tractor engineer here. You typically see sprung tensioners on high quality drives that see variable loading. Why? The belt tension is held to a low constant regardless of the loading allowing long life for the drive.

Many belt manufacturers advise their V-belts run to a 5:1 tension ratio (although ratios as low as 10:1 run fine without slippage).

View attachment 4209485
Here is a typical drive with 5:1 tension ratio at full load. Wonderful. Look what happens to tensions when the loading is lightened or the drive stops:

View attachment 4209531

Now add a backside sprung idler tensioned for full load.

View attachment 4209532

Same result right? Now analyze at low or no load:

View attachment 4209533
Huge difference... belt tension lowered by 1/3!

If a drive only see's constant loading (air compressor for example) a sprung idler doesn't offer much advantage. If a drive will see variable loading (like mowers).... a sprung idler lowers tensions considerably and increases life on belts, sheaves, and bearings. Adds cost though. Hope this helps!

Bravo!!!!!!!!!!!!!!!!!!!! Well Done.

Now if we could only have trash doors installed on our flail mowers
everyone would have less work to do to change knives and have
no plugging in thick tall brush.

 

[Doug Vee]

I see often mentioning of V-belt tension gauge which makes me wonder why are the manufacturers not using spring loaded tensioner, like shown in my old Ford 917L Special below - perhaps it's just cheaper to make them without one?

I bought this mower five years ago as a fixer upper and it has worked out very good without any need to mess with the belts, once I figured the correct belt length.

This is obviously light duty mower with side slicer flails and it does a nice job in mowing a field, as well as forested area, without any scalping.

This thread has been very helpful for me!


View attachment 4184713 View attachment 4184711 View attachment 4184719

I like the idea of an auto tensioner. It seems like it would be one less thing to remember to check.

 

[dadohead]

Yup.... a no-brainer. These are not high quality drives. Even if you buy a gadget to measure belt tension, what tension do you set it to?

 

[RjCorazza]

Yup.... a no-brainer. These are not high quality drives. Even if you buy a gadget to measure belt tension, what tension do you set it to?

True. My Del Morino doesn't even specify what to adjust the belt tension to. I made an educated guess to adjust the deflection to 1cm midway between the pulleys with moderate thumb pressure.
After maybe 100 hours the belts look great, so hopefully I'm in the ballpark!

 

[leonz]

Yup.... a no-brainer. These are not high quality drives. Even if you buy a gadget to measure belt tension, what tension do you set it to?

The tension gauge measurement markings are used to do that for the specific belt size.

 

[dadohead]

The tension gauge measurement markings are used to do that for the specific belt size.

Correct belt tension is based on knowing the loads, not belt size.

 

[leonz]

All V belts have a certain amount of stretch that is managed by proper creating the proper tension.