Concave cone burs

I can’t seem to find any examples of people working with these (reviews/tutorials). In photos they look just like a cup bur, but I’m looking for a quick and easy way to make little spikes out of a wire end (10-14ga) or a soldered-on ball for edgy/rock n’ roll designs. I primarily work in sterling, but sometimes fine silver and brass/bronze as well. Can anyone with first hand experience describe the finished shape these leave and if they’re what I’m looking for? Specifically, I am considering the Busch® Tungsten Vanadium Twincut Concave Cone Bur at Rio and I’d like to keep my costs as low as possible as I am an amateur doing experiments.

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I live close to this tool supplier. 've gotten the tool in this link from them n as large as 1 gauge. Contact them and see i you can get the size you want. No need to buy expensive burs, and no electricity needed. They work perfectly. I use them when I do ear ring wires.

But what shape does it leave? It looks like the standard cup bur, which is not what I’m looking for. As I said in my post, I want to make spikes, not just round off an end.

Could you just put your lengths of wire in a flex shaft or drill and grind (spin the wire against a flat surface) on sandpaper at an angle?

I don’t think I’ve seen a bur that leaves a sharp tip and I can’t imagine many use cases justifying their production. But if you just want to make a bunch of tapered spiked wires this is what I would do. Saves you from having to file each individual wire by hand and probably makes quick work of shaping and polishing your tapered spiked.


I have a PUK and use it to create a smooth rounded end to earring wires and post. It won’t create a ball much larger than the end of the wire. I also regularly solder what I call a 3/4 ball to the end of 12 gauge wire to create a hook that is part of my hook bracelets. I just melt an amount of jump rings that will create the ball. Keep a record of the size of jump rings used so that you can repeat the process. I then put the ball onto a dapping die block and either with a hammer or my 20 ton press, force the ball into a die hole slightly smaller than the ball. This does two things: it makes the ball round and it closes up any imperfections in the surface. Finally, if I wanted to sharpen the end of a piece of wire, depending on the length, I would make sure that it is straight, chuck it into an electric drill and run it against a 600 grit sanding disc making sure that they both run in opposite directions. If the wire is too long to use the drill, use a pin vise and turn the end against the sanding wheel by hand. This may or may not help answer your question…Rob

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These are just regular cup burs that do the opposite of what you are looking for- they round off sharp edges.

concave cone burs result in a slightly different shape than cup burs…

cup burs result in a low, rounded dome
rounded side profile

cone burs result in a low, rounded cone, which does have a sort of a point, but i would not call it a sharp spike, because its profile is shallow…
flatter side profile


Yeah, I think I’ll just do that and save the scrap dots for something else like impression die stuff or ingots