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does any one know if the blade bolts are reusable. and if not, a cheaper place to get them other than a dealer. i work for a municipality and i bet we throw 100 blades a year mowing ditches and bypasses.

Yes, use them over.
Found your bolt $1 cheaper at website above.

do you know if there made to pull out when you hit something? what is happening is we'll hit something and the blade with bolt still in it will fall off

what year is the mower?
2009 year says they have a ribbed hex bolt, others just say "hex bolt"
Are the bolts breaking, or just falling out, like they came unscrewed?

2018 329 b rear discharge. the bolt threads almost look pulled when they come out. im pretty sure there not unthreading. i have looked a the parts break down and all it shows is hex bolt. question is can i use a good grade 8 bolt and be good?

Apparently it is a grade 8, fine thread.... i see the six radial lines as well on the head....

All my manuals say if you strike an object in the field, the bolt needs to be inspected and tightened immediately for it will fall off.

If threads inside spindle are good apply Blue Loctite to bolt threads before installing.

You are mowing in one of the worst conditions possible and when a blade hits a correct object the blade momentarily stops and loosens the cap screw never to be tightened unless you stop and tighten it. If the cap screw looks anything but pristine condition I would replace it.

SeniorCitizen said:

You are mowing in one of the worst conditions possible and when a blade hits a correct object the blade momentarily stops and loosens the cap screw never to be tightened unless you stop and tighten it. If the cap screw looks anything but pristine condition I would replace it.

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Sorry but you really need to think this one through, draw it out on a piece of paper if you need to.
All mower decks are designed to self tighten in use so the bolts can not loosen when the blade momentarily stops
The blade may stop but the spindle does not so the bolt gets tighter
However the blade can spin inside the cups that hold it to the spindle and deform or wear a shallow groove , just enough for the blade to go a little loose .

Back to Rosco
First as a municipal authority you should be able to get them ( and all your parts ) directly from GrassHopper at trade price.
Also because you are a municipal authority you should be able to get swing back blades.
I know that Walker do swing backs, I am about to replace a set this week
Next have a good look at the cup washers, they have probably gone flat & are no longer doing their job of holding the blades tight under spring pressure .
Your diagnosis is probably correct, they are getting over tightened and are necking, so some Blue locktite as Mark suggested might be the answer and be careful not to overtighten them from the start

are bolts torqued to specs. when installed?

You missed the whole concept.

thanks every one for the input. this week ill be checking the spindles and cup washers over good. and i belive lock tight is always a good idea.

incredible!!

i doubt they are torqued. just took over maintenance for this street department. i bet they are just run in with a 1/2" rattle gun. trying to get all this junk up to snuff for next season

Grasshopper like to use a fibre washer or two to clamp the blade , these wear thin over time so fail to clamp the blades tight enough.
If properly tightened you should be able to engage the PTO clutch and then turn the motor over by rotating the blades
Fine threads are very shallow so it is very easy to deform the threads
If the bolts are perpetually falling out then I would suggest replacing the spindles because pounds to peanuts the internal threads are stuffed .

Most mower manufactures do provide torque specs for tightening the blade bolts. Depends on the bolt size and grade and thread type fine or coarse. You should be able to find a generic blade bolt from a bolt supply company. I know we buy from Hillman that supplies all types of hardware and bolts. I know they have some grade 8 flange head blots not sure if they have fine threaded ones or not.

That's why I asked the question, if torque is done then proceed problem solving. Those guns just bounce, especially with bevel washers causing low torque.
Seen some stone wall issues!

STEVES said:

That's why I asked the question, if torque is done then proceed problem solving. Those guns just bounce, especially with bevel washers causing low torque.
Seen some stone wall issues!View attachment 58945

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OWCH!

after talking more to the guys running the mowers. They are reusing the old fiber washers or just not using them at all. found that the cup washers are all flat. so we will be changing all the cup washers. the spindle threads all look to be in ok shape, was told to get at least one more season out of the spindles before we change them management has put a stop to the crew working on there own equipment, so i will be very busy.

Check to see if Grashopper have a swing back option
They are the bees knees for council work where you are forever finding vent covers, stop valves, sprinklers, broken posts etc in the long grass.
Not like mowing your own grass at home where you can walk around & clean up first .