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Blade on too tight

Posted by gregnga 7 (My Page) on
Sat, Apr 13, 13 at 16:09

My lawn mower shop has a habit of putting my blade on so tight I can't get it off without bringing it back to them. Can some one suggest a tool/way I can get it off myself next time


Follow-Up Postings:

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RE: Blade on too tight

  • Posted by baymee LehighValleyPA (My Page) on
    Sat, Apr 13, 13 at 21:30

Disconnect the spark plug wire. Turn it up on its side with the carburetor facing up and the gas tank less than half full. Use a block of wood to prevent the blade from turning. Use a wrench or socket and a long pipe which fits over the end of the wrench or ratchet. It will come loose.


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RE: Blade on too tight

Remember these words of instruction: Lefty-loosey/ righty-tighty! From the sage of mower fixers. RJ!


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RE: Blade on too tight

Impact Wrench. That put it on, that will take it off.


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RE: Blade on too tight

PB blaster???


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RE: Blade on too tight

Your mower shop is over-torquing the bolt. Most mowers use a 3/8-24 blade bolt (9/16" wrench), which should not be torqued beyond 60ft/lbs for a Grade 8, and less for a Grade 5.

Toro uses a 7/16-20 bolt (5/8" wrench), which torques to 80ft/lbs max. for Grade 8. Also some riding mowers with large single blades also use 7/16 -20 bolt.

Next time they have the mower, tell them you want the bolt torques appropriate to the size and grade of the bolt. As an earlier poster suggested, they are probably using an impact wrench, and banging as hard as the wrench will deliver.

Remind these guys that too much torque is just as dangerous as too little torque, and if the bolt fails because of their practices, they will be involved.


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RE: Blade on too tight

I have never failed to get one broken loose using 1/2" breaker bar and pipe extension. I also use pentrating oil and 2 by 4 wooden block cut to proper length and notched so it catches the blade good.

I guess mower shops are like tire shops. Most know they are suspose to torque to spec's, but most use the impact wrench cause we don't like to wait and this saves 30 seconds.


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RE: Blade on too tight

I have failed to get some off using conventional methods.that were obviously put on with an impact. I have had to grind the heads off the bolts and in one case, weld a nut on the bolt after cutting off the head and removing the blade.

While 60 lbs is max recommended by most, I use torque wrench to 40 lbs. 60 lbs is to keep blade from spinning loose when electric PTO is disengaged and required blade brake engages. I have had no problem at 40 lbs.

Walt Conner


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