Stone setting burs won't cut!

[Siskin]

I am just getting started with stone setting, and have a question about the use of stone setting burrs.
I have a selection of Busch burrs.

I'm starting with a drill, then removing the bulk of material with a ball burr, and then attempting to cut the finished seat with either a stone setting burr or a hart burr.

The problem I have, is that the stone setting and hart burrs don't seem to cut! It almost feels like they are permanently clogged up, and all they seem to do is polish the metal and get very hot.

I am using "cut lube" on all burrs, as recommended by Cookson, and have also tried beeswax. My material is sterling silver.

What am I doing wrong?

[Dennis]

There can only be one obvious reason: your machine is in reverse. Dennis.

[ps_bond]

What speed are you running at, and was there any chatter when using the ball burr?
TBH, I don't think you'll find many setters using setting burrs as standard - the hart burrs are useful for undercutting bearings sometimes, but it's the ball burrs do the heavy lifting.

[Siskin]

There can only be one obvious reason: your machine is in reverse. Dennis.

Definitely not in reverse! Drills and ball burrs cut just fine.

[Siskin]

What speed are you running at, and was there any chatter when using the ball burr?
TBH, I don't think you'll find many setters using setting burrs as standard - the hart burrs are useful for undercutting bearings sometimes, but it's the ball burrs do the heavy lifting.

I run the ball burrs slowly, and they seem to grind away metal efficiently. No chatter. I started the setting burr at about 5,000 rpm (2mm diameter burr), and gradually increased all the way to 20,000 rpm when it didn't seem to be doing anything.

[josef1]

you need to run the burs as slow as you can, the slower the better 100 rpm slow .If they are getting hot they will be dead.

[Ruedeleglise]

Yes. I have a 5mm setting burr that I over revved by mistake. Not only did it heat up the silver very fast and “burnt” my fingers, it also went blue! No use at all now!


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[Dennis]

If that is the case, and your machine cannot be run slowly enough, when you buy new setting burrs, also get a universal handle, https://www.cooksongold.com/Jewellery-Tools/Universal-Handle-And-2-Chucks-prcode-999-AZM
Tightened in one of those, you can easily refine the seats by hand and preserve your burrs for longer.

The preferred lubricant at hand speed, is a tiny drop of oil. Dennis.

[Siskin]

Thank you all for the tips and suggestions!

[ps_bond]

Just to put some numbers on it - when running a burr up to 1.5ish mm I usually run it at 3krpm. A larger burr, with it's greater diameter (and therefore circumference) needs to go even slower rotationally to get the same linear speed.

[Sheen]

There can only be one obvious reason: your machine is in reverse. Dennis.

I just did that today. Mmm why are my drill bits not working. I can't understand it!!!:rofl:

[Sheen]

If that is the case, and your machine cannot be run slowly enough, when you buy new setting burrs, also get a universal handle, https://www.cooksongold.com/Jewellery-Tools/Universal-Handle-And-2-Chucks-prcode-999-AZM
Tightened in one of those, you can easily refine the seats by hand and preserve your burrs for longer.

The preferred lubricant at hand speed, is a tiny drop of oil. Dennis.

I've used setting burrs in a hand vice and it works well, if anything you can be more careful doing it this way.

[Ruedeleglise]

I have just dug out from my “thought would be a good bargain but didn’t cut the mustard” draw a small hand held Utool I bought on Amazon for some project. The yellow one. It has 3 speeds. On low speed the power couldn’t knock the skin off a rice pudding. Having said that I have used it for some delicate work setting 2mm stones. It is very light and easy to manipulate and I found it great. Any pressure and the tool stalls so I had no heating up problems at all. I have rather arthritic hands so this takes a lot of the “grind” out of repetitive work. Anyway, so far so good.


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