Why did this happen?

[koop]

This is a Woods mower with about 20 hours of use. This is what it looked like after a hit a rock. I have hit many rocks before that did not do this. I was wondering if this is normal.

http://www.tractorbynet.com/forums/attachment.php?attachmentid=107612&stc=1&d=1217842332

 

[Farmwithjunk]

Not "normal", but not impossible either. Looks like you nailed a rock "just right" and bent the blade upwards. A couple weeks ago, I caught a rock "just right" with a Bush Hog mower that ended up with the rock getting between the blade end and the deck. That bent the blade downward approx. 6". Put a heck of a dent in the deck and ruined a blade.

 

[koop]

After banging for about 10 minutes, I managed to dislodge this blade. When I held it next to the other one, I could not see any significant difference in shape.

 

[Farmwithjunk]

After banging for about 10 minutes, I managed to dislodge this blade. When I held it next to the other one, I could not see any significant difference in shape.

I'd take carefull measurements and look closely to see if the stumpjumper isn't bent. Something had to give a little to allow that blade to end up several inches out of place. With the blade re-installed, measure tip of blade to deck on both sides. Should be the same measurement OR start looking for something misaligned.

 

[RonMar]

Stumpjumper/hub could be bent. deck/gearbox mount could also be bent. Re-install the blade and measure distance from blade tip to deck with blades fully extended, with the hub rotated around to different places around the rotation. In a perfect world, it should be the same from tip to tip all the way around... the forces involved under a brushhog deck in operation are awesome, and when a high mass immovable object is struck, a whole lot of different things can happen. How are the bearings in the gearbox(wiggle blades up and down and look for vertical play in blade mount or hub movement)?

 

[koop]

I will raise cutter this weekend and measure all around to look for uniformity. I did notice that I was able to tighten the nut on non-embedded blade a little. Is it possible that the blade was loose enough to create the play needed to allow it to hit the deck?

What other damage will have occurred as a result of this do you think. I noticed that the shaft still turned when I spun the blades by hand.

Thanks for the help.

 

[RonMar]

I will raise cutter this weekend and measure all around to look for uniformity. I did notice that I was able to tighten the nut on non-embedded blade a little. Is it possible that the blade was loose enough to create the play needed to allow it to hit the deck?

What other damage will have occurred as a result of this do you think. I noticed that the shaft still turned when I spun the blades by hand.

Thanks for the help.

IMO, yes a loose blade bolt could contribute to this.

 

[Soundguy]

Hogged out hole in the blade for the bolt could do it too.

soundguy

 

[pitt_md]

I have wacked a few big rocks and thought that SOMETHING had to be messed up under the deck only to find that things look just fine. Amazing what these things can take.

 

[schmism]

there are supports for the deck on the underside?

mine are on top with a perfectly smooth underside... i guess it would eliminate that problem..

 

[Bentwrench]

If I recall right, that is a boxed support beam on the under side of the Wood's brush cutter. A stump or rock at the wrong timing or a loose blade will let this happen. You want to repair the box support not only for strength but also to keep trash from hanging-up and making more problems.

 

[wrenchturner]

Koop, you've got to change that Avatar. Almost killed my monitor.

 

[Window Geek]

Koop, you've got to change that Avatar. Almost killed my monitor.

Wooo hahaha! Me too! **** fruit flys! Hard to kill those little bahstids!

 

[pitt_md]

there are supports for the deck on the underside?

mine are on top with a perfectly smooth underside... i guess it would eliminate that problem..

Mine is smooth under the deck as well.

 

[Squeak n Itch]

Neighbor of mine, under the influence of an overdose of Saturday morning caffeine hit a rock and opened up the deck as though done with a can opener!!

 

[Charlesaf3]

I've hit my fair share of rocks with the woods, haven't had that happen yet!

Its possible to bend the tail wheel yoke, though, it appears... despite being really heavy steel.