Balancing brush cutter blades

[BobRip]

I have a wobble in my brush cutter on my PT422. Has anyone got a good procedure for balancing the blades? I figured that you connect the two blades together with a bolt and put a fulcrum under where the blades meet. Sharpen till balanced. Any comments

Bob Rip

 

[beenthere]

If I follow you, I don't think that will work.

I use a balancing cone that the blade sets on. Others use a nail in a post, or a screwdriver with a round shank. Or a nail in a vice, such that the blade hole can be placed over the 'round' and if it remains 'level' then each end is similar in weight.

But two blades bolted together? Doesn't seem it will give you a good answer for each blade individually.

 

[MossRoad]

Weigh them on a scale.

 

[NJBill]

BobRip
JUST A THOUGHT
Because the blades were supposedly, originally made identical, I would think that as you are trying to grind equal parts from each blade, the use of a balance scale, postal meter, or some other equivalent, would give you equal weights.
A normal mower blade has to be balanced one side with the other,so making one same weight as the other, should bring you very close to your expectations
Bill

 

[Bird]

Like MossRoad and NJBill said, I had some scales that would register up to 20# (used primarily for weighing my rabbits), and I just hung the blades on those, one at a time and made sure they weighed the same.

 

[beenthere]

Question?
Are we talking of balancing between blades? or balancing within one blade, end for end?

 

[tracdoc]

the brush cutters have a PAIR of diametrically opposed swinging blades spinning on the same hub, hence the need to balance one to the other. Take a lookee at underside of MR's unit {HERE}

 

[BobRip]

Yeah, that's what it looks like. The unbalance is not severe, so weight match might be enough. I will try the bolt method first.

Bob Ripley

 

[beenthere]

Ahh! the lightbulb just came on, duh!
Thanks for that pic. It's a good one for reference.

I see now where I was off track here, and sorry for pulling this thread off track. /forums/images/graemlins/blush.gif

 

[BobRip]

No problem. I should have described the situation better.

Bob Rip

 

[pequeajim]

</font><font color="blue" class="small">( Weigh them on a scale. )</font>

Thats is EXACTLY right. Althought not much of a tractor guy, I fly large scale helicopters and beyond lateral and chord, the most important thing is tp put both the heli blades on a scale and weigh them, then balance them on a sesaw type of balancer.

I would think it is the same principle for any swinging blade set.

 

[RegL]

Never weighed or balanced the blades on my 60" PT brush hog and it runs so smooth I have to take a peek at the motor some times to make sure it's running. If it started to vibrate, I would be looking for something other than unbalanced blades. Maybe loose motor mounts or bent stump jumper or maybe worn bearings. Just my thoughts but I think the blades would have to be way off to get the brush hog jumping around.

 

[MossRoad]

When mine starts jumping, it is usually the blade stuck on the bolt that is supposed to stop it from getting stuck on the other blade /forums/images/graemlins/tongue.gif

I'll have to try the fix about putting in a longer stop bolt and washers that was mentioned several times over the years, but I have been too lazy to do. /forums/images/graemlins/grin.gif

 

[BobRip]

This was not a severe unbalance, but you could see the entire bush hog wobble a little bit. No feel in the PT422. I balanced them last night by using a scale and it's a lot better.

Bob Rip