Blade Bolt torque

Old 06-17-18, 06:52 AM
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Blade Bolt torque

I rescued a Toro "Select a pace' mower" without a serial number tag. My best guess is that it is a 2002 model with a 6.5 hp gas engine, and although it has a bag option, it is touted as a "recycler" and has that decal on the deck. It has a factory blade on it and installs with just one bolt into the crankshaft. What is the proper torque to apply to this blade bolt?
Old 06-17-18, 07:14 AM
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I do mine at 85 lbs. 100 is too tight while 70 lbs is too loose . . . . but 85 lbs is just right.
Old 06-17-18, 08:35 AM
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Although I have torque wrench I hardly ever use it. As long as it does not come off, tight is good. I don't understand how 100ftlbs is too much (other than trying to get it off for maintenance).
Old 06-18-18, 07:52 AM
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A dealer Video suggests 60 ft #s for this model, I can see that a dealer rec torque would be good to follow for liability purposes. I can see the advantage for tightening to just hold it on, especially for people who don't check for rocks or other debris before mowing. (could save a crankshaft or two)
Old 06-18-18, 08:21 AM
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I think if you are walking behind it, you never want that sucker to come off. Can be a little hard on the toes.
Old 06-18-18, 11:19 AM
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The torque is going to depend on the size of the bolt so will be different for different machines.
In this case too tight is not a bad thing but it is possible to over torque a bolt and weaken it.
Old 06-18-18, 12:27 PM
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As BFHFixit said, proper torque depends on the fastener size. It also depends on the fastener and clamped materials, the joint design and if a thread lubricant is used. If you are really determined to torque the bolt you can probably find a torque app on the internet.

However, in your application I think "grunt" torque is probably OK. If you are really concerned about the blade coming off "star" torque ("tighten that sum'***** til you see stars") will also get it done.

The six levels of torque as taught to me many years ago by a really old shipyard mechanic that still had most of his fingers.

Finger tight
Hand Tight
Wrench tight
Grunt tight
Star tight
Nut droppin' tight.
Old 06-18-18, 04:26 PM
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I own 7 different mowers, we mow over 75 lawns a week for the past 10 years and I've never once torqued any of them and have never even had a blade come loose.
I use a 3' ratchet so my hands are not under the deck and it gives me more leverage.
Sometimes I need all of it to get the bolt out.
The direction of rotation is such that the bolt stays tight.

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