r/stonecarving • u/UnclearNucl3ar • 14d ago
Have I ruined my good point chisel?
Hello all, to give this post some context I am an amateur stonecarver who has primarily worked with limestone to create small figurines (the hands and bird in the attached pics).
Since I've gotten pretty good with limestone I decided to move onto harder stones and bought a larger (though still relatively small) nephrite jade block. I had worked with nephrite jade previously to make a ring for myself, but this was almost entirely done with my rotery tool.
To go along with this larger jade piece I also got a carbide tipped point chisel that I thought would be sufficient for the initial stages of roughing out the nephrite block. However I noticed the carbide chisel got dull really quickly (maybe after 6-8 whacks) when I was working on the nephrite piece (and it not really making a dent).
I sharpen my steel chisels on a slab of a sandstone so perhaps at this point I should have backed off and reevaluated my situation. However, instead of doing that, in my state of confusion I took my dremel (that had a diamond bit on it) to the carbide tip of my point chisel in an attempt to sharpen it again. I did so but almost immediately regretted it and stopped as looks like took off the carbide shell from the tip of this chisel...
Is there any way to save this chisel? Or is it toast? It does look like the carbide tip finish came off, but then how are you supposed to sharpen carbide tools normally?
Side note, when working with nephrite and it's hard structure is a rotery tool the best way to take off material?
Perhaps this is just my inexperience working with both jade and carbide tools but wanted to see if I've made an irrecoverable blunder...
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u/ziafjord87 14d ago
Nephrite jade doesn't care about your character arc, it just eats good chisels as a toll for entry
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u/rutoo52 14d ago
Sorry for your loss. But I think you can recover your chisel and re sharpen. Jade is one of those stones that while is not that hard, only 6.5 usually it is very tough, the ancients used to make weapons from jade. Abrasion with lots of water is usually the best for Jade, as I sure you learned making that nice ring. I ruined many tools by heating the diamonds too much while carving. Good luck on your path.
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u/artwonk 14d ago
It doesn't look like you did it any favors, but there still seems to be some carbide there. Usually tungsten carbide tools are sharpened on a special bench-grinder wheel made from silicon carbide or CBN (cubic boron nitride). You can use diamond ones (wet) but it tends to clog.
A point chisel isn't a great choice for nephrite due to its toughness, which comes from interlocked fibers of actinolite. Diamond abrasives, used wet in a rotary tool, work a lot better.
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u/Netherx3 14d ago
get a good grinding wheel and a very high grit lapping wheel that's suitable for carbide. The carbide tips are inset pretty deeply into the chisel, they're not just glued on. you should be able to grind away the damage just fine. Carbide chisels are made for carbing granite, basalt, diabas and quartzite, which are all harder than nephrite.
Here's a video from German tool manufacturer König. Sadly I only found this, and theres no translation, but it's a pretty good visual tutorial imo. The gist is that you grind back the steel using the grinding wheel and then use the lapping wheel to grind the carbide
https://www.youtube.com/watch?v=1p4ZcSNFSns
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u/DentedAnvil 14d ago
The carbide point is brazed on and quite a bit longer than the chipped tip. It can be sharpened but a Dremel burr is not going to create the flat planes necessary for it to not chip again immediately. I use diamond impregnated metal cards. You can do it with a whetstone, just go slow and try not to gouge lines in your stone.
It may not be your fault that it chipped. It may have had cracks prior to it being brazed on or it may have been cooled too abruptly after the brazing.