I'll be working with square-cut Pennsylvania bluestone cleft flagstone nominal 1" thickness. Before I actually do anything, I'm trying to come up to speed on splitting flagstone with a tracer chisel. I've read that it's possible to ruin a carbide tracer chisel by misusing it, though the nature of the misuse was not described. I have no idea what that misuse might entail. Striking the chisel with too much force? Holding it at the wrong angle? What things might a newb do with a carbide tracer chisel that shouldn't be done with it?

P.S. I might not even need carbide. Will a plain steel tracer chisel be sufficient for PA bluestone flagstones?

  • 1
    Misuse of any tool will ruin it. Misuse can be using the tool in a way it is not made for, like using a screwdriver as a chisel, or dropping it from on high to a hard surface. Using a tracer to trace lines should be good, splitting the stone not so good.
    – crip659
    Aug 26, 2022 at 19:57
  • @crip659: A "tracer" chisel is for creating fault lines in the stone so that it fractures where you want it to. It is not merely a scribing tool.
    – mr blint
    Aug 26, 2022 at 20:48
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    @SolarMike: If you have nothing factually relevant to say, please at least refrain from snide ad hominem remarks. Who said anything about me thinking I was an "expert"? I explicitly referred to myself as a "newb".
    – mr blint
    Aug 26, 2022 at 20:51
  • So if you keep pounding on it in one space till the stone fractures/breaks might be misuse.
    – crip659
    Aug 26, 2022 at 20:53
  • @crip659: You don't have to comment on a question if you're just as ignorant about the subject as the person asking the question.
    – mr blint
    Aug 26, 2022 at 20:53

1 Answer 1


I was able to find some maintenance and use tips for carbide stone working chisels.

Using a dull edge can break the weld, so do not delay in sharpening the carbide if you notice performance is declining; keep the edge sharp and at the same shape it was when new, maintaining the bevel on the edge. Use an 80 grit or higher green silicon carbide bench grinder wheel or electroplated diamond pads, taking care not to remove any of the steel that supports the carbide. Do not quench the carbide cutting end with water or oil when sharpening, let it air cool.

Grind the hammer-struck end of the chisel using an aluminum oxide wheel before it becomes splayed as splaying can lead to cracks in the steel which is a safety hazard; when grinding the hammer-struck end don't let the steel get too hot as that will soften the steel; keep an eye out for discoloration in the steel and cool the hammer-struck end in water often during the grinding process.

Here are errors a novice might commit that constitute "misuse" of the tool:

When using the chisel always maintain full contact of the edge with the surface of the stone; do not strike with the chisel corner only or allow part of the carbide edge to sit on a high spot with the rest of the edge unsupported. Never insert the chisel in a crack in the stone and never use it as a wedge or lever.

EDIT: A corollary to the above rule about maintaining full contact of the chisel edge with the stone: when dealing with a rough surface with high spots, choose a narrower chisel that fits between the high spots.

Even though carbide is very hard don't assume it is indestructible; the carbide is brittle and can crack when struck at an oblique angle.

  • interesting read ... always maintain full contact of the edge with the surface of the stone ... how is that even possible on a rough stone surface?
    – jsotola
    Aug 28, 2022 at 17:57
  • @jsotola You're not asking the right guy :-) But from my reading I believe the aspiring stone-mason would set the tracer chisel aside and switch to a "pitching" chisel, which is more heavy-duty.
    – mr blint
    Aug 29, 2022 at 21:26
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    @jsotola: The underlying principle is that you don't want to have an extreme concentration of force on a small section of the edge. As long as you make adjustments to the angle of attack so that the forces are spread over most of the blade, it should be OK. A small gap would present far less risk of damage to the carbide than a small high spot leaving the rest of the edge unsupported.
    – mr blint
    Aug 30, 2022 at 11:50
  • @Jsotola: Further in regard to the high spots: use a narrower chisel to avoid having the chisel edge straddle a high spot. The rougher the surface, the narrower the chisel.
    – mr blint
    Sep 6, 2022 at 20:33

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