Rotary Cutter Balancing rotary cutter blades

[SCDolphin]

Does anyone have a method for balancing rotary cutter blades as they are being sharpened??

Thanks

 

[CCWKen]

Make a simple beam balance scale out of a piece of 2x4. Or if you have an accurate scale, weigh them. I've found it takes a big difference to cause vibration. I suppose because of the low rpm. It's not like a lawn mower blade that will shake the engine apart.

 

[greg_g]

Does anyone have a method for balancing rotary cutter blades as they are being sharpened??

Well, since they're not symmetrical like a finish mower blade, you can't actually balance one blade. What I do is weigh them. When I've got the edge I want on the first one, I weigh it and set it aside. When I have the edge I want on the 2nd one, I weigh it also. The heavier of the two gets a little more ground off, 'til it's within an ounce or so of the other one.

//greg//

 

[DMF]

Well, since they're not symmetrical like a finish mower blade, you can't actually balance one blade. What I do is weigh them. When I've got the edge I want on the first one, I weigh it and set it aside. When I have the edge I want on the 2nd one, I weigh it also. The heavier of the two gets a little more ground off, 'til it's within an ounce or so of the other one.

//greg//

That's exactly what I do as well.

 

[john_bud]

I don't worry about it.

Just grind the buggers off and go.

jb

 

[RickB]

I don't worry about it.

Just grind the buggers off and go.

jb

Exactly. My blade management consists of replacing them in pairs only, and sharpening both when they are dull. Generally I do not tolerate bent blades.

 

[Farmwithjunk]

3 batwings and 3 single spindle mowers on the job this past summer. So, 24 individual blades. All the batwing blades are the same. All the single spindle models use the same blades. We sharpen most of the in place, never removing thm from the mower. They get ground "as needed", with very little attention paid to matching weights. With both types, I keep several spare blades on the service truck. If a blade gets bent or broken, they get replaced as needed. No attention is paid to matching as they're replaced. And in the end, no ill effects or no out of the ordinary vibrations to report.

Long story short, I wouldn't take any extrordinary measures to balance bush hog blades.

 

[em14]

I never even worry about ... there is a need once in while tho not often to sharpen if you are "hogging" "cutting pasture" but if you are a finish cutter for real nice yards you may want to sharpen more often ...
Leo

 

[JDeerekid]

I sharpen my right on the mower also. Just sharpen and eyeball to see if they are approx the same. I sharpen mine maybe twice a year depending on what I am mowing.

 

[TORQUIN]

I tried the balance method, not having a scale accurate enough to weigh them handy. I will say that balance does matter, but I can't qualify that with how much. I sharpened both my blade and reinstalled them on the Howse 5' cutter I have, after attempting the balance with a piece of 1"x1" with knotches cut near the ends. While the stick alone was almost perfect, my knotches must have been off a little because no matter which blade I put on one side it always tipped that way.
Anyway, after the install I had a vibration in the cutter that I could feel all way through the tractor, so I figured those blades must be WAY off. I pulled them and ran it with just the stump jumper. No vibration, so I ran up to Tractor Supply and picked up a couple of new blades. Vibration is gone with the new blades. The next day I ran that cutter through very heavy pasture and small trees for 8 hours with no problem, and no vibration.
If anyone has any good balancing ideas, or can recommend a scale that would be suitable for this, I'm interested.

Chris

 

[greg_g]

If anyone has any good balancing ideas, or can recommend a scale that would be suitable for this, I'm interested.

Can't quite follow your balancing technique, but weighing them is no problem. For less than the cost of one replacement blade, you can buy a digital postal scale. Mine weighs up to 60 pounds in 0.1 ounce increments. When shopping for one, I saw up to 70 pounders for under $35. Matter of fact, there's a 52 pounder on eBay right now for ten bucks.

//greg//

 

[skipmarcy]

I've sharpened my 6' Howse blades on the unit about 3 times a season for 10 years and never had a balance problem - one set of new blades in that timeframe. When I bought those new blades 5 or 6 years ago I heated & bent the little ears up to help with lifting the grass some too and caused no balance problems.

 

[have_blue]

Long story short, I wouldn't take any extrordinary measures to balance bush hog blades.

Agree 100%. I grind my blades on the machine too, and try to grind them equally to maintain a ballpark balance. If I ever get vibration that feels as though it could be doing damage to the gear box (or the seat of my pants) I will attempt to balance them. No problems so far in 9 years.

Dirt dobber nests on the stump jumper will probably cause more imbalance than unequal blades.

 

[SPYDERLK]

Check to see if you have a bent blade. One swinging lower than the other by an inch will cause vibes.
larry

 

[Farmwithjunk]

Check to see if you have a bent blade. One swinging lower than the other by an inch will cause vibes.
larry

YEP! And it's easier to bend a blade than one might think. A well placed rock of the right size will do the trick. They can get between the end of the blade and the deck, bending the blade just enough to shake the daylights out of a mower. BTDT, tossed a BRAND NEW blade in the scrap pile......

 

[wedge40]

I have an OLD Bushhog SQ72. It's built to last and I think the heavier the machine the better it will tolerate out of balance blades. If you have a light duty machine then it wont take as much to feel out of balance blades.

Wedge

 

[Transit]

Make a simple beam balance scale out of a piece of 2x4. Or if you have an accurate scale, weigh them. I've found it takes a big difference to cause vibration. I suppose because of the low rpm. It's not like a lawn mower blade that will shake the engine apart.

Sorry Ken, my 5 ft King Kutter spins at 2,000 rpm more or less.

 

[SPYDERLK]

Sorry Ken, my 5 ft King Kutter spins at 2,000 rpm more or less.

Less if it has a 5' cutting element vs two 2.5' elements.
larry