Setting burrs

[ps_bond]

FYI, the scorpers on the tool list for the course were a bullstick (size 21), flat (size 12), round (size 8) and spitstick or onglette (size 10). The bullstick was the go-to tool for cutting bearings, while the spitstick was mostly used for cutting away metal from the grain settings; the round wasn't really used for anything other than raising grains and the flat was almost exclusively for bright cutting. They're very versatile tools and well worth learning to sharpen and use.

[theresa]

Hi everyone

I have a question in a similar vein. I am trying to set a 6mm faceted stone into a tube setting & the stone is a tad too high and sitting slightly unevenly. I know I need to deepen the seating but cannot find a 6mm ball burr anywhere. Should I be using some other tool for this job? I understand the principles of this type of setting but as it is my first would welcome any advice.


Theresa

[lopez]

Hey Theresa, some stone setters would use a ball bur, some a setting bur and some a hart bur, either way it's not the method but the result what matters. In your case looking at the photo the walls look rather thin, therefore pop the stone out if you can, stretch the collet out a touch with a round mandrel if you have one the make the correct seating with a small (<6.00mm) ball drill, file and shape the top of the collet, use a ~1.00mm ball drill to make an notch around the internal diameter where the collet meets the girdle of the stone then put the stone in making sure it's level then push the collet over the stone starting at 12 then 6, 3 then 9 o'clock; when thats all done push the rest of the metal over. File and shape the top, lube the top of the stone and bright cut the inside collet then bright burnish, all good ???

[Kwant]

I would be lost without my setting burrs, which certainly go to 6mm and beyond I got mine at Fischer in Germany I got this box when it was on special offer.

http://www.goldschmiedebedarf.de/pro...ducts_id=25560

but they can be bought individually.

[Dennis]

A full set is rather pricy, but you never know quite which size you will need next, as even stones of the same nominal size will vary when they arrive.

My biggest problem is keeping them in order, so I am forever checking them with callipers. Guess what I shall say next: yes, I think you need callipers as well.

While on the subject of Fischer, they do a useful assortment of round burrs too, the largest being 10.0mm. Round burrs are cheaper to replace and cut faster, so that the setting burrs can be reserved for the finishing touches. Both will cut by hand, assisted by a drop of oil, if mounted in a pin vice. Dennis.

[theresa]

Thanks to everyone for the advice. I have managed to track down some burrs from Cousins so will let you know how I get on. Examining my stone closely I noticed the girdle is thicker one side than the other which accounts for the uneven seating...more work....and this was supposed to be an inexpensive ring!
Theresa

[Dennis]

. ...more work....

Not necessarily Theresa, because the difference will be slight and your seat could be a little wonky. So rotate the stone until you find that the table is level, steady it with a fingernail. and start setting.

At worst all you do is slope the burr a little for the last few turns to create a deeper side, or deepen one side with a tiny round burr. Dennis.