i have a craftsman 3 blade ride on mower and one day after mowing a
field of tall grass i turned the blades off, the center blade just
fell off the shaft onto the ground.
i just thought it a fluke wierd thing, so i sharpened the blade and
took the other two blades off to sharpen and balance them as well,then
put them back on.
excited to mow with sharp blades i started her up and took off for the
field.it worked perfectly.
i mowed the field and when finished i shut the blades off only to find
end blade had droped off the shaft.
i thought perhaps i had not tightened the bolt enough, so i torqued it
down as much as i could.
just to find that on a trial blade run it does the same thing. quite
i cannot find anything on lawnmower blades just falling off.
does anyone have any suggestions???
i thought so at first, but checked immidiately, and that's not it.
i wondered if perhaps the blades were clipping each other causing one
of them to unscrew the bolt, but there seems to be clearance.
On Mon, 22 May 2006 16:20:06 -0700, redskygroup wrote:
If the blades made contact, you and the rest of the neighborhood would
know for sure! The noise and the resulting damage would be quite obvious.
The bolt should never "loosen" up by it's self. The bolts always (in every
mower I've ever had) screw down the opposite direction of the blade spin.
So in theory the bolt should tighten while the blade spins.
I asked my toro guy about the bolt loosening up and that's what he said.
Then he took me out back, hand tightened my blade bolts, started the
blades for a mineut and shut it down. He lifted the deck and I checked the
blades and they were on good and tight. I needed a socket set to get them
off again. By no means should one do this to install the blades, but the
exercise was all about showing me that the blade bolts are ment to self
tighten and if I screwed up the blade install I should be safe.
I would suspect that you have a bad bolt, a bad spindel or bad blade. Look
to see if the bolt has been striped or is worn somehow. Mount the blade
and see if the blade is bent. A bent blade could vibrate the bolt off.
Last, inspect the spindel to ensure that the threads are not damaged and
the spindel is not bent.
That's the reason I cautioned about using them, because I knew you
didn't have a clue about the use of different grade bolts. I suggest
you read up on metal grades before suggesting someone switch bolts on
anything. The one thing I've seen the most mis-used in my years as a
mechanic is grade 8 bolts.
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