"Identical" blades = expensive lesson

AlohaMowing

LawnSite Senior Member
Location
Hilo, HI
I needed new blades for my 72" Turf Tiger 2. One (and only one) of the two Scag dealers on the island claimed to have them in stock. When I arrived to pick them up I noticed that the part number pressed into the blade was 482880. The part number shown in the owner's manual for TT2 blades is 482882.

I later found the 482880 is listed by Scag as the blade for a 72" Cheetah and I will refer to them as the TT blade or the Cheetah blade.

I said "that part number is off by one digit." Dealer employee says they are identical and pulled out a rusty blade with 482882 pressed into it -- the TT blade. They looked the same other than the rust, and the sharpened edge on the Cheetah blade was about 1" more than the sharpened portion of the TT blade. They apparently had only one of the TT blades in stock so I said fine, I'll take 3 of the Cheetah blades.

I thought all was good until shortly after the Cheetah blades were installed and I had started mowing. The rural mowing I do is relatively rough, especially where feral pigs have been digging. With each rough patch one of the Cheetah blades dug a circle in the turf.
IMG_0770.JPG

Some of the divots were 2" deep at the edge. I slowed my mowing and it still happened. I raised the deck and it still happened. Several times the blade took such a solid bite that it stalled the engine. Twice a blade took such a solid bite that the deck belt broke, each belt costing over $80 plus shipping (because local dealers did not have them in stock).

After breaking the second belt I stopped using the TT until I could get some genuine TT blades shipped to me. Once I swapped the new TT blades for the Cheetah blades the problem stopped immediately and completely.

So it had to be something different about the two blades. Certainly the little bit extra sharpened edge on the Cheetah blade could not explain it and there was nothing else about the appearance that differed even slightly. Being limited in my resources to analyze the blades I put them on a scale. Each Cheetah blade weighed 50.4 ounces. Each TT blade weighed 63.5 ounces. Wow, so each TT blade was 26% heavier than the Cheetah blade. Comparing the thickness of the blades I cannot detect a difference, let alone that the TT blades would be 26% thicker.

The only thing I can figure is that whatever alloy is used to make the Cheetah blades is lighter than that used in the TT blades, and the Cheetah blades must have been flexing to dig down at the blade tips, and once they got a little bite of soil they would chomp in firmly.

I should have known better than to accept that the blades were identical. If they were, surely Scag would use a single part number to simplify stocking parts. Anyway, while the dealer was to blame for passing off the Cheetah blades as identical, I must accept some fault.

So using the "identical" blades not only wasted time and caused numerous unsightly circles in the turf, but also cost me about $175 for the two broken belts. I shall be less trusting in the future. And this makes me wonder about all those blades sold online that claim "replaces part number 482882."
 

Derwood

LawnSite Bronze Member
Location
SE Wisconsin
It was only one blading digging in like that? Or was it the left blade one time, the right blade another time etc. Did all three ever dig in at the time?
 

JayinKs

LawnSite Senior Member
Did you put the spacer on the wrong side of the blade or is the new blade set an offset type blade?
 

Derwood

LawnSite Bronze Member
Location
SE Wisconsin
I’ve made that mistake before .... just plain old not paying attention, or talking to the neighbor while putting stuff back together. The cut is higher at that blade.
 

Valk

LawnSite Platinum Member
Location
KS
Sounds like one blade was upside down?
 

Derwood

LawnSite Bronze Member
Location
SE Wisconsin
Yeah While cutting my last account I was thinking about the weight thing. I don’t think there’s any way the weight difference has anything to do with it. Even if those blades were 2 pounds heavier each that would not do that. You have heavy duty spindles and a heavy duty deck. 2 pounds lighter wood not flex like that either. Plus aren’t all of our mowers turning 3600 RPMs?
 

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