# Is a torque wrench necessary for putting on a mower blade?



## ryeguy

The manual to my timemaster suggests this, but I'm curious if this is actually needed or if it's just something they're saying to protect against undertightening.


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## Greendoc

I think overtightening is worse. Snapped bolts or bolts that will not come off the next time. Most of us are strong enough to overdo it.


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## Mightyquinn

When I used a rotary mower and I would change the blade or sharpen it, I wouldn't use a torque wrench and just make sure the bolt was nice and tight. I've never had any issues with it coming loose or being difficult to remove. When tightening the bolt down, just don't go overboard with it and make sure it's torqued to German specifications "gutentight"


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## Pedro built

there cheap and makes me feel good about it but almost nobody uses one and you rarely hear of blades coming off.


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## j4c11

I just tighten it as far as it will go with my impact wrench 

No, seriously :lol:


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## TulsaFan

Lopezpslc said:


> there cheap and makes me feel good about it but almost nobody uses one and you rarely hear of blades coming off.


The length of the bolt used to secure the blade would cause some extreme scalping before the threads fully pulled out.


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## gene_stl

The direction of the screw threads are usually such that as you mow the threads get tighter. They need to be tight enough so that there is no slippage. Then they will tighten as you mow. I always put some copper anti-sieze on the bolts. You could also use almost any grease. I have always used a torque wrench and the torque specs are always unbelievably tight. (118 ft lbs on my Hustler , 120 on the orange monster) That is hard to do without an extension, while you are also keeping the blade from turning with a two by four. (for a fat old geeb like me)

The Hustler has "Belleville spring washers" which have a very visible dish shape. They have to be put on correctly (obvious)
and when you torque them down they mash flat and put a lot of locking force on the spindle. The Hustler spindles have a large almost three inch diameter flat for the blade top to bear on. Way overkill compared to any residential mower I have ever changed blades on.

As previously mentioned torque wrenches have gotten cheep. But I think a half inch drive breaker bar would be good enough. Half inch drive is important.


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