Usually a carbon arc torch. A messy substitute for an oxy-acetylene rig. They used to come as a matter of course with farm/garage arc welders. There are a few other uses in welding. I have two in my rathole that I’ve never used.
If memory serves: If you take a D cell, lay it on something hard and hit it a couple of times to soften it up, then roll it 90 deg and hit again…etc, you can pull out the carbon with no real trouble. Then grind it to a point and you are good to go.
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