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Posted

I need to make some stone carving chisles for someone and I need an idea of what kind of steel to buy. I figure I will buy some sort of 1/2 in drill rod or tool steel. Any suggestions would be helpful.

Posted

Go to the nearest rental outfit and ask for old paving breaker bits, often called "jack hammer bits" they should be free for the asking. Good steel there.

Posted

Most commercial drill rod is O1 or W1, which both have about 1% carbon. That makes heat treating trickier, and reduces toughness somewhat. Stick with something a little lower in C, as suggested above.

Posted

I would buy new S1 tool steel it's made for that kind of work. Old rock drills are unknown steel alloys though most likely water hardening. Jack hammer bits are 1045 most of the time but if you are making fine edged tools for delicate carving it is not the way to go. Why put all that time into a tool only to have it snap or be too soft because you did not use the right kind of steel or know how to properly heat treat it.

Posted

What kind of rock carving? 40' cubes of granite or small alabaster or soapstone carvings, or small jade carvings?

Harde stones will profit more from high alloy chisels. Soft stones can use easier to find and work materials

Posted

MattBower wrote, "Most commercial drill rod is O1 or W1, which both have about 1% carbon. That makes heat treating trickier, and reduces toughness somewhat. Stick with something a little lower in C, as suggested above."

I have some old unknown drill rod on hand and it's nice stuff. I suspect this material is left over from an old coal mining operation 100 years ago. At any rate the stuff spark tests very high in carbon. It made about the dandiest cold chisel I've ever used. I wouldn't hesitate to make stone (granite) carving tools from it.

The biggest problem with drill rod is the hole down the middle for the pneumatic air blast. That has to be cleaned and closed. Beware, there are reports that this drill rod was sometimes used to tamp in the blasting powder. Be certain the bore is clean before heating it. What I did was cut off a short section with an abrasive wheel, chase the hole with a long 1/4" drill bit and then brush it out with a .270 cal cleaning brush and solvent. Then I packed the bore with borax and brought it slowly up to forge welding temperature. I just closed the business end. Starting about 4" from the end I bashed the crap out of it with a single jack, forcing the flux out the end as I went. I took a second heat to shape the chisel At that point I polished it and took a third to heat treat it. I water quenched from dull cherry red - just about 1-1/4" of the tip and only for a few seconds. Then I watched the temper colors run back to the point and quenched again at straw. I've beat the hell out of this chisel and it never folds the tip or chips. Really impressive stuff.

But much easier might be to just find an old bent or broken hexagonal pry bar and use a chunk of that. Should be plenty high carbon.

Posted

"What kind of rock carving? 40' cubes of granite or small alabaster or soapstone carvings, or small jade carvings?

Harde stones will profit more from high alloy chisels. Soft stones can use easier to find and work materials." ThomasPowers


Yes to that. Also, the driven end is different for steel driving hammers or wood.

Posted

Ahh Tom, most places not in mining country "Drill Rod" refers to stuff you buy at a good hardware store and is generally O1 or W1. It does not contain a center hole as it's not purposed for rock drills but for steel drills. In England they would call it "Silver steel".

Living in mining country I too have a stash of the "old good stuff" that sparks like a file when tested! I also run into a bunch of old tools forged from it out by the mines, and in scrap yards and fleamarkets

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