How hard do you run the edge on a pitching chisel?

I've made a handful of pitching tools and bolsters from car springs and axle stock, and I land in the softer camp for anything that's going to hit granite. My main walling chisel is drawn back to around a dark straw, maybe just past it, and it dings up plenty but the edge actually mushrooms instead of chipping, which you can dress on the grinder in five minutes. A chip out of a hard edge means losing way more steel getting the notch out than you ever lose to routine dressing.

That said, on limestone and sandstone I'll run things harder becasue the stone forgives you. Softer stone is abrasive more than it is impact, so the edge wears away instead of taking hits, and a harder temper just means longer between touches. I did a sandstone patio a couple summers back and never redressed the pitcher once in three days of work. Granite is where the whole debate matters. Glancing blows on a hard inclusion will take a chunk out of a brittle edge every time, and I learned that the expensive way on a set of tungsten carbide tipped tools where the tips themselves fractured. Since then I err tough and just plan on touching up.

Your forklift tine stock shold have plenty of toughness in it either way, so I'd say you're in good shape no matter where you land.

I run my pitching tools way harder than most folks here would recommend, and I mostly work limestone and sandstone, so take that for what it is. I've got one made from a worn-out S7 jackhammer bit that sits around a light blue at the edge, and it holds a sharpening for whole retaining wall jobs. On limestone the stone gives up before the steel does, so I figure why leave all that hardness on the table. When it finally dulls I dress it once and keep going. The tradeoff flips with granite though. I learned that the hard way on a granite step job where I used the same tool and rolled three chips out of the edge in an afternoon. Caught a glancing blow on a hard inclusion and the corner just popped right off. That was the day I made a second, softer tool specifically for granite work. One thing worth flagging on your forklift tine: those are often some medium carbon alloy and you don't really know which, so your color run might behave differently than the same heat on known steel. I test scrap off the same tine, quench a stub at full hard, then break it in the vise and look at the grain before I commit the real tool. Cheap insurance when the parent metal is a mystery.

So my answer is make two, or make one and just temper it for the stone you cut most.

Still pretty green here so take this with a grain of salt, but I've only ever made cold chisels for splitting brick pavers out of big bolts and a chunk of rebar I shouldn't have used. Never got into color tempering, I just quenched and hoped. The harder one chipped the first day so now I keep everything soft and dress constantly, which sounds lazy reading these replies. Question for you though, since you ran colors on your tine: how do you eyeball when a mushroomed edge is too far gone to dress and better off just re-forging? I've been guessing and one of mine is basicly a thin fin now.

Been making pitching tools off and on for years and honestly I stopped overthinking the temper question. I run two of the same pattern, one soft, one harder, and grab whichever matches the job. Sounds wasteful but forging them takes me an afternoon now and it beats ruining a good edge halfway through a wall.

One thing I'd watch with that forklift tine, some of that stuff work hardens wierd and can crack if you quench it too fast. I've had better luck normalizing a few extra cycles before the hardening heat.

Update: the mushrooming point from the spring-stock guy stuck with me, so I ran my second one back to dark straw and caught a flint nodule in a sandstone bed with it. Just left a little shiny dent, no chip. Guess I'm making a pair of everthing from now on. Question though, do you mushroomed-edge folks ever dress those dings out or just keep hammering?