Brush hog blade snap & flies...

[IslandTractor]

I was bush hogging by backing into brush yesterday when I heard a "wham" and then lots of vibration from my Woods 600 Brush Bull. I stopped and checked under the mower (and saw the rock I'd hit). A six inch piece of the blade had broken off. Luckily it was sitting about four feet away rather than shooting off towards nearby houses.

When I checked the piece I noted that the fresh fracture was actually only about an inch of the 4 inch by half inch blade. The blade must have been fractured some other time in the past.

I have another set of blades so will install those and then double check the slip clutch (which was reset this spring). I suspect the combination of the previously partially fractured blade and the sudden shock of hitting a fair sized rock (forty pounds or so) simply completed the fracture so the slip clutch was not at fault.

Photo shows the broken surface of the blade tip and the other shows the recovered piece next to the new replacement blade.

Questions:

1) Do any of you check blades for cracks regularly? If so how?
2) Do you guys always replace blades as pairs? Is there any benefit to holding on to the unbroken older partner blade to use as a spare down the road or are "mismatched" blades a risk. Both original and replacement are Woods brand.

 

[jlsmith]

If you replace one blade then you replace both of them. If not you could get it off balance and end up damaging the gearbox.

 

[sweettractors]

I was bush hogging by backing into brush yesterday when I heard a "wham" and then lots of vibration from my Woods 600 Brush Bull. I stopped and checked under the mower (and saw the rock I'd hit). A six inch piece of the blade had broken off. Luckily it was sitting about four feet away rather than shooting off towards nearby houses.

When I checked the piece I noted that the fresh fracture was actually only about an inch of the 4 inch by half inch blade. The blade must have been fractured some other time in the past.

I have another set of blades so will install those and then double check the slip clutch (which was reset this spring). I suspect the combination of the previously partially fractured blade and the sudden shock of hitting a fair sized rock (forty pounds or so) simply completed the fracture so the slip clutch was not at fault.

Photo shows the broken surface of the blade tip and the other shows the recovered piece next to the new replacement blade.

Questions:

1) Do any of you check blades for cracks regularly? If so how?
2) Do you guys always replace blades as pairs? Is there any benefit to holding on to the unbroken older partner blade to use as a spare down the road or are "mismatched" blades a risk. Both original and replacement are Woods brand.

Does Woods still use 3/8 inch thick blades on the cutters? Ken Sweet

 

[IslandTractor]

Does Woods still use 3/8 inch thick blades on the cutters? Ken Sweet

Mine has a 4 inch by half inch blade

 

[D7E]

Ex employee of ours had a blade come off a disc mower ..break the back window and slice his scalp open, Many drum and disc mowers do it as they get old with worn or weak blade hangers then hitting a small rock .

 

[sweettractors]

Ex employee of ours had a blade come off a disc mower ..break the back window and slice his scalp open, Many drum and disc mowers do it as they get old with worn or weak blade hangers then hitting a small rock .

I don't know about drum mowers, but, most disc mower mfgrs suggest replacing the blade bolts each time you put on a new set of blades. Ken Sweet

 

[RickB]

Does Woods still use 3/8 inch thick blades on the cutters? Ken Sweet

No, they are thicker 1/2" I think.

 

[D7E]

I don't know about drum mowers, but, most disc mower mfgrs suggest replacing the blade bolts each time you put on a new set of blades. Ken Sweet

Many disc mowers like PZ drum mowers and many others use a sprung hanger instead of a bolt . Blade change in seconds just by levering the hanger down .
Come with a tool much like a tyre iron that you lever and just slip the blade in ...job done.