Blade balancer for MMM blades?

JackJ

Member

Equipment
BX1870-1
Mar 14, 2016
264
3
18
Indiana
I've got the RCK48-18BX deck on my BX. I've purchased two different blade balancers, the cone type with steps, but none of the steps match up with the center holes on my blades.

Anyone have an economical option with better accuracy than a nail on the wall that will fit Kubota blades?
 

SidecarFlip

Banned

Equipment
M9000HDCC3, M9000HD, Kubota GS850 Sidekick
Oct 28, 2018
7,197
546
83
USA
Never balanced any blade but then they get renewed every spring.
 

Freeheeler

Well-known member

Equipment
b2650 tlb
Aug 16, 2018
704
519
93
Knoxville, TN
The spinning mass only needs to be balanced in the plane of rotation. In other words, a nail in the wall is a very accurate way to do it, and cheap. The thinner the nail, the better.
 

GeoHorn

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M4700DT, LA1002FEL, Ferguson5-8B Compactor-Roller, 10KDumpTrailer, RTV-X900
May 18, 2018
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Place a smooth-sided funnel over the "stepped" cone and balance your blades placing your blades holes over the funnel.

(Most static balancers are very crude anyway. It's why tire shops no longer use static balancers... all of them having graduated to dynamic balancers. Imagine a blade with uneven radial-density caused by sharpening. (more material removed at the end of the blade on one end...and an equal amount removed from the middle of the opposite end. The blade will balance just fine when on a static balancer such as the bubble/cone/nail systems. But put that blade in motion and centrifugal force will cause the blade-end with more material at the end to out-weigh its opposite end...and the vibration will be noticeable!)
The only way to accurately balance the blades will be while spinning at operating speeds, but that is beyond the capability of most homeowners.... so the "nail" or simply hanging/suspending it from a wire is the best that can be accomplished.
 

JackJ

Member

Equipment
BX1870-1
Mar 14, 2016
264
3
18
Indiana
Thanks for the input. As to whether it's necessary: I do hit the occasional rock when mowing, and when my blades get out of balance, I can feel more vibration coming through the mower deck. I'm assuming that it could lead to earlier spindle bearing failure, but not sure.

I sharpen with a flap wheel on an angle grinder, and it's a simple matter to make a few extra passes on the heavy side of the blade to balance it out.

But I hadn't thought about the difference between static and dynamic balancing, and can see how that might make a difference. I'm hoping that by removing material from the full length of the cutting edge, rather that just from the tip, I'm still getting consistently improved results.

Even if the only benefit is a slightly smoother ride, there's no reason not to do it, imo, given that it typically adds just a few minutes to the sharpening routine.

My previous mowers' blades all fit fine on the cone balancers, and I was happy enough with the accuracy. I've tried the nail on the wall, but I got much less repeatable results with that method.

The quality balancers from Oregon and others go for $80 - $90, and I'm not willing to spend that much. So I'm now thinking about a bearing with the right o.d. to fit my blades, and that I can mount somewhere on a vertical surface in my garage. Cheap enough to give it a shot.
 
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Freeheeler

Well-known member

Equipment
b2650 tlb
Aug 16, 2018
704
519
93
Knoxville, TN
Thanks for the input. As to whether it's necessary: I do hit the occasional rock when mowing, and when my blades get out of balance, I can feel more vibration coming through the mower deck. I'm assuming that it could leave to earlier spindle bearing failure, but not sure.


But I hadn't thought about the difference between static and dynamic balancing, and can see how that might make a difference. I'm hoping that by removing material from the full length of the cutting edge, rather that just from the tip, I'm still getting consistently improved results.
Static balancing is well within tolerance for a blade to prevent any damage or noticeable out of balance feel. With hitting big rocks your bigger problem is with bending the blade. A bent blade, even if balanced statically, can cause noticeable vibrations and can cause spindle or mount damages.
 

JackJ

Member

Equipment
BX1870-1
Mar 14, 2016
264
3
18
Indiana
For $5 at Home Depot and a few minutes for balancing 3 blades seems almost senseless not to balance them.

Thanks, D2Cat--I agree!. I've got both a plastic and metal version of this style. But it bugs me that neither have a step that's the right diameter for my Kubota blades. They still work when I eyeball the centering, but it'd be nice to find one that fits the blade hole correctly.
 

William1

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BX25D
Jul 28, 2015
1,080
263
83
Richmond, Virginia
I've never had to balance a blade. I sharpen so both cutting edges look the same. I have checked balance a few times and it was fine. Three sharpening's and I replace the blades.
I only have a acre to mow, nothing worse than tiny twigs and leaves so I only sharpen once a year.
 

SDT

Well-known member

Equipment
multiple and various
Apr 15, 2018
3,084
923
113
SE, IN
Static balancing is well within tolerance for a blade to prevent any damage or noticeable out of balance feel. With hitting big rocks your bigger problem is with bending the blade. A bent blade, even if balanced statically, can cause noticeable vibrations and can cause spindle or mount damages.
Agreed.

Bent blades are an entirely different matter.

SDT
 

BobInOK

New member
Jun 3, 2019
79
0
0
Catoosa, OK
Know anybody with a lathe? Would be pretty easy to make a bushing, little more difficult to make a complete balancer to fit the blades but can be done.