Black & Decker lawnmower. How to remove blade from electric
lawnmower? Model MM525 which is very much like the MM575.
Is there a simple, or complicated, way to keep the motor shaft from
turning, when trying to loosen the nut on the end of the shaft?
I have to remove the blade to replace the fan and the manual says to
use a 2x4 to keep the blade from turning. I do keep the blade from
turning, but the nut and shaft turn together anyhow, so there is no
I figured if I broke the plastic fan off, I might have enough room for
vise-grips. Do you think they could nick, whatever, the shaft enough
to unbalance it?
(FTI, a third of the plastic fan was broken off so I tried to knock
off the rest with a hammer. It cracked easily and fell off in
suceessive pieces. Unfortunatately, that was stupid because I also
cracked the blade spacer, a cast metal piece, that now I have to
replace. :( 3 dollars and a trip to the store, 10 miles away.
Fortunately I have to drive by there next week anyhow.)
Thanks a lot.
On Sat, 27 Jun 2009 08:46:40 -0700, "Jon Danniken"
Thanks for replying.
Do you mean the impact wrench one hits with a hammer**, or the kind
that usually uses compressed air, but comes in electric also?
**I have a manual impact wrench and I did think of it, but I figure it
might put too much longitudinal force on the bearings, and I wasn't
sure there was enough mass in the shaft and armature for it to work
Aye, sorry, not the manual one (I have one of those too). You can get the
pneumatic kind that requires a compressor, which are the most common, but
they also sell electric ones.
If you don't have a compressor, I have heard that the electric ones from
harbor freight do an acceptable job.
On Sat, 27 Jun 2009 09:47:43 -0700, "Jon Danniken"
Yeah, I see they have a 12 volt Harbor Freight model for 25 dollars.
It says it has 150 foot pounds with a good battery, and 30 to 40 blows
per minute (BPM).
Then there is for 50 dollars an AC model withe 240 ft.pds and 2400
And for 40 dollars an 18 volt battery model, 3/8", 87 foot pound, 1700
Rudy, Tim, I can't just use a socket wrench because even when I hold
the blade still, the nut and the shaft turn.
Thanks Bob and William, the manual said nothing about being
left-handed, and based on the direction the blade turns, I don't think
The possibility is that sometime you hit something and that impact
stretched the bolt (or shaft if it really is a nut on a shaft; that
would be unusual for anything but electric but I've not had an electric
so perhaps they do).
If that is so, the impact wrench is probably about the only hope. If
that is the cause for it being so tight, you're looking at a replacement
Had it happen on one of the blades on the 6-ft belly mower; took a 3/8"
pry bar through the upper drive pulley as a backup and that bar simply
bent rather than the bolt coming out.
It would be the whole motor armature. :) BTW, that ebay armature
used to show the threads was only a dollar this morning, and sold for
6.50 plus 12.25 shipping. A good price I'm sure, but I can buy a new
one if I ever need it.
Not sure of the problem. I have a similiar model....or used to ...the
CM1000...you used the wood to jam the blade and you just "unscrewed
it." It was pretty simple. If you are having problems, there may be
more wrong than something simple, because it is really pretty simple.
Wear gloves though when doing this.
This is an ancient thread, but I just came across it today as I was running
into the same problem. I wasn't happy about trying to get hold of an impac
e wrench, so I kept messing around until I figured out what I could do with
hand tools. In case anyone else needs it, here's what I learned today by t
rial and error: The bolt, and by extension the motor, do turn with the nut,
even if the blades are immobilized. However, there is a rectangular plate
behind the nut, and a plastic plate behind that. If you immobilize the meta
l plate with a pair of vise grips placed around the edges of either plate,
though preferably directly on the metal one, in addition to immobilizing th
e blades with the 2x4 (thereby placing less strain on the vise grips), this
will keep the bolt in place while you turn the nut. A bit of liquid wrench
didn't hurt, either.
On Saturday, June 27, 2009 at 11:46:40 AM UTC-4, Jon Danniken wrote:
You can try a short box wrench and small hammer. The inertia of the rotor
should enable you to use them as a primitive impact wrench. The type impact
driver you strike on the end with a hammer would also likely work with a
little patience and skill. Of course, a power impact wrench would be the
I don't recall the model I have (it is battery powered), but I
just sharpened the blade for the first time a few days ago. A gloved
hand held the blade while a box wrench turned the bolt holding it on.
It was threaded normally and did not require an unusual amount of
If stopping the blade doesn't stop the shaft then what drives the
Something is wrong. Somehow the blade is slotted, flat sided,
or some other means of coupling is suppose to take place. Push
the blade down onto the shaft while turning the nut.
On Mon, 29 Jun 2009 12:45:29 -0400, email@example.com wrote:
The blade is on tight enough that the motor will spin it, and it cuts
well. But it's not on tight enough to hold the shaft in place when
trying to unscrew the nut on the end.
There was a picture which was about balancing the blade after it is
sharpened, and it showed the center hole as round.
I broke a part on Friday, and just got it today, Monday. I'll probably
work on it tomorrow and I plan to let you all know tomorrow night, if
the thread hasnt' gone up into the wild blue yonder.
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