Yeah, a lot of the metals used to make tines these days are pretty soft and don't hold much if any kind of an edge. And to no fault or failiure on the manufacturers.... they use the softer stuff for a reason: it's a bit safer to let a tine get mangled, than the operator. There's also a drawback: lighter materials mean a lighter machine that likes to bounce out of the ground.
Safe or not, I got sick of machines that were to light & fluffy to get things done. So I built my own tiller from salvaged bits and parts from stuff I felt would suit my needs better. First glance one might think my rig is a factory unit...untill you look closer. I kyped things off other models that were handy, and eliminated other things that just got in the way. My tiller will not win an award for the safest thing on the planet any day soon. Not to say it's absolutely unsafe to
use it however. At any rate, I pay very very careful attention to what I'm doing when I'm working with it, even more so with the custom tines I use.
My sod buster set looks a lot like the blades on an old JD rototiller. 6 bars about 4.5 iches from center to outer edge, with mild angles on them. Short, 3.5 inch wide semi flat buggers, not long and finger-like. Hardened steel, these things cut sod up fast. (6 bars, 3 on each side of the tiller) These are a pita to sharpen!
The mulch set is a trio of 5 inch long fingers (again from center to outer edge) 3 fingers per "wheel" if ya call em that. Semi hardened steel with a short angle on each finger. (again, 6 units with 3 on each side)
The cultivator set is a pair of long-finger tines each set 90 degrees from the other. 2 units per side. Each "finger" on these is about 8 inches long or so. These guys I made myself, and are super easy to put an edge on.
I've spent years picking rocks and roots out of my soils. I don't usually run the sod busters unless it's new or untouched ground for someone else.
I run some rather soft sheer pins. Seems to keep my tines in nice shape when they bite into something mean. I've also seen my machine stay in the ground and keep goin while my inlaw's rig bounces right out of the dirt if so much as a dandelion is in the soil. I attribute that more to the fact that I built my frankentiller
rather heavy. The chassis without a motor weights more than 150 pounds.... and I've also got a 60# counter weight on the nose. I also have a second 40# I can put on the rear if needed. Wich is rare, but comes in handy when doin soddy/new ground. No reverse on the cuss... so once you start a path... it's gettin done! My machine is ugly no doubt... but it does just what I need it to do.