These blades are from my dad's Toro walk behind mower dual blades. He went to check the blades and found the trailing edges pretty worn out. The leading edges have no nicks and he rarely hits yard debris. Both end are like this Maybe just airflow going over the top as there is an upsweep? He was more curious why this happens. I can see why it would cause blade balance issues or having a fragment fly off.
The upturn gets sandblasted off over time from bits of sand and small gravel that get picked up. If you have sandy soil this will happen quicker.
When my wife used to mow we would get a weird wear on the bladea. They would be all bent up and twisted! I think she aimed for any object that was laying in the yard! Gary
Yep, i get one season out of mower blades, i dont even bother sharpening em, as they get worn out just knockin the weeds down and suckin up all the sand.
Yup the wear is abrasion from sand. Just replaced the gator blades on my big mower, 62" JD 2305 with Yannmar diesel. Got 11 year mowing 3 acres weekly. Guess I should not complain. The top mulching edge didn't have much of an edge left and I couldn't sharpen that.
My old neighbors would hit the same roots and rocks every single friggin week. Like nails on a chalkboard......
Switch to a low lift blade as they are not that tall and can't wear what isn't there. I went from high lift blades to low years ago and get almost double the life out of them.
My buddy's neighbor would mow right across their gravel driveway every time she went around. She had the mower set on scalp...and it took at least a dozen laps around house...we laughed/cringed every time... Like you said...nails on a chalkboard!