Rotary Cutter Wobbly 5 Foot Woods Rotary Cutter?

[vern6973]

Hi:

I took the 2 blades off my 2006 5' Woods rotary cutter, sharpened them and put them back on. Now the cutter shakes real bad. The blades were put on the same way they came off.

Are these large heavy blades that balance sensitive to having some of the steel removed during sharpening?

Also, is there a rule of thumb on when these type of blades should be replaced?

Thanks:
Vern From Illinois

 

[Couple of Achers]

This is a stretch, but make sure both blades still pivot on their mounting bolt. If one is not fully extended, it would throw it out of balance a lot. I have seen one blade that had folded back towards the mounting bolt and had locked there. I think the mounting bolt was installed upside down and the blade hit on it. It was a long time ago and I don't remember exactly what the cause was, but just make sure everything underneath still moves as it is suppose to.

As far as replacement goes, it kind of depends on whether you are happy with it's performance. Before I got rid of my first one, the blades looked more like clubs. Very rounded off. But for what I needed if for, it was still worked.

 

[whistlepig]

This is a stretch, but make sure both blades still pivot on their mounting bolt. If one is not fully extended, it would throw it out of balance a lot. I have seen one blade that had folded back towards the mounting bolt and had locked there. I think the mounting bolt was installed upside down and the blade hit on it. It was a long time ago and I don't remember exactly what the cause was, but just make sure everything underneath still moves as it is suppose to.

As far as replacement goes, it kind of depends on whether you are happy with it's performance. Before I got rid of my first one, the blades looked more like clubs. Very rounded off. But for what I needed if for, it was still worked.

I would check for a folded blade also. You would have to grind off a pretty good hunk of metal from one blade verses the other for it to vibrate this badly. Or your blade mounting bolts may be cocked or not be seated all the way.

 

[mark_torrey]

good suggestion on checking for proper swing. also, good to remove the blades and check for matching weight. they should be fairly close in weight. +/- a few grams should be enough. if not, then remove material from the heavy one, then reinstall.

To make a simple suspended scale:
+ select a wooden cloths hanger (or select a wood or metal dowel), strong enough to support the combined weight of your blades.
* if using a dowel, measure and mark the exact center
+ measure and mark ~1 inch in from each end
* if using a dowel, tie a string at the center mark
+ cut two 8-10 inch pieces of heavy wire (14 gauge copper, baling wire ... etc)
+ measure and mark each wire about 4 inches from one end. wrap a wire tightly around each end of your hanger (or dowel) using the mark as a start point. leave enough wire to twist around itself a couple of times, to keep it on the end of the hanger or dowel.
+ hang your scale high enough to allow the blades to hang free of the ground or floor.
+ make a hook on the other end of the wire to be inserted through the mounting hole on the blade. If your wire is not strong enough to hold he blades weight, pass enough wire through the blade to create a loop, then hook onto the wire above the blade.
+ hang one blade on each wire.

If the blades weight the same, your hanger or dowel will be level. The heavier blade will hang lower then the lighter blade. Remove, grind edge, rehang ... repeat until blades hang level.

Hope this helps ...

 

[whistlepig]

With all due respect I'll buy me some new blades before I go through all that.

 

[mark_torrey]

Well hey, I gotta tell ya, it sounds more complex than it is.... shouldn't take more than a couple of minutes to make ... I have a similar scale, hanging in my work area which I've added a vertical wire to 'align with the center string' to show level. When you have to sharpen blades, you appreciate them being in balance. I have two shredders (Texan for rotary mower), a 6ft (w/1 set) and a 14 ft (w/3 sets) of swing blades, so the scale serves me well.

Sharpening blades regularly gives you a better cut, saves wear on the gear boxes, spindles and reduces overall vibrations. Facilitates monitoring mower and blade conditions, and to better determine when replacement due to excessive wear, is necessary.

Regards,

Mark

 

[vern6973]

This is a stretch, but make sure both blades still pivot on their mounting bolt. If one is not fully extended, it would throw it out of balance a lot. I have seen one blade that had folded back towards the mounting bolt and had locked there. I think the mounting bolt was installed upside down and the blade hit on it. It was a long time ago and I don't remember exactly what the cause was, but just make sure everything underneath still moves as it is suppose to.

As far as replacement goes, it kind of depends on whether you are happy with it's performance. Before I got rid of my first one, the blades looked more like clubs. Very rounded off. But for what I needed if for, it was still worked.

Jerry:

Thanks, the bolts have a slotted key and one wasn't quite in the groove. I took the blade off and re-installed ... runs smooth again.

Vern In Illinois