what a dumb design, the blades aren't keyed?, I would torque the cup washer to blade at the proper torque, then I would weld the cup washer to the blade itself. Ridiculous design.
98ft lbs on those small 10mm threads sure seems excessive
Is ZD326/331 the same setup as ZD1211 in the pic illustration in post #5 ?
Assuming the op has the bellview washers oriented correctly, I would be inclined to torque the bolts a little more. Perhaps add a 3rd washer and increase the bolt torque if there is enough thread (I've never added a 3rd washer).
I don't use a torque wrench on the blade bolts for my zd326 or zd1211, but I'm sure I keep them tighter than 98 ft/lbs.
I take the blades off to sharpen every 2 weeks or so, and have never had a problem with them.
virtually all? I have personally seen it once, I have worked on maybe 50 different riders over my years, and all of the ones I worked on had a star variant stamped blade which is what kept it in place on the on the spindle from slipping, that said I have not worked on more industrial machines, usually lower end consumer grade stuff.Basically all zero turns along with virtually all other riding mowers use round hole blades. I don’t know what bases for comparison you’re using to say it’s a terrible design. I would venture to say the Kubota zero turn is the strongest design on the market. Kubota has a shaft drive deck. Basically all the others use a drive belt that slips under high load. The Kubota uses a double belt to drive the blades that’s last upwards of 1k hours. Virtually all the others use a single belt that only last a few hundred hours. The Kubota blades use a splined washer on the blade that’s better than just a regular bolt that virtually all the other zero turns use.
Never had a round hole blade that didnt also have pin holes. My ZT uses pin holes.Basically all zero turns along with virtually all other riding mowers use round hole blades. I don’t know what bases for comparison you’re using to say it’s a terrible design. I would venture to say the Kubota zero turn is the strongest design on the market. Kubota has a shaft drive deck. Basically all the others use a drive belt that slips under high load. The Kubota uses a double belt to drive the blades that’s last upwards of 1k hours. Virtually all the others use a single belt that only last a few hundred hours. The Kubota blades use a splined washer on the blade that’s better than just a regular bolt that virtually all the other zero turns use.
Heavy duty commercial has round holes. I kept sharp blades handy and changed 66 blades a week. Basically half the mowers every other day. Kept a few new blades to replace ones too worn. They'd wear in two on the back side where they turned up. I welded some of those back and used them again.Never had a round hole blade that didnt also have pin holes. My ZT uses pin holes.