stone setting burrs

I purchased a stone setting burr from Rio Grand and it just doesn't seem to cut, more like a grind and it leaves a wire edge around the pocket. First, I am just learning and want to bead set stones in buckles. So I may not know what I am doing. I have watched Sam's stone setting video on youtube. I have tried to follow it. Is it me or do I just have a poor quality burr. I know just like everything else; you can buy junk or pay more for quality. Another question is what size hole do you drill before using the burr. If the stone is 3mm What size drill is required?

Yes ,there area lot of junk burs out there, be careful and pay attention to brands and configurations so you can get what work for your application. I use 45* for bead setting. Predrilling is a good idea, If your hole needs fit a 3mm stone the hole should be drilled with a 1.5 and then use an undersize ball burr (2.5) to help get proper depth and then finish with the correct size setting bur,the stone should sit plum and just have enough depth to allow you to raise a bur(prong) that crowds the girdle and come over the top of the table. Most of the time I use a #52 Round bottom to raise the bur. Good luck!!!! Amethyst and emeralds are not very suited for this !!!!!!!!!!!!!!!!!!!!!!!!!!!!

Make certain your grinder is running in the correct direction. My NSK micromotor is easy to select the wrong direction.

silverchip said:

Amethyst and emeralds are not very suited for this !!!!!!!!!!!!!!!!!!!!!!!!!!!!

Click to expand...

I remember turning emerald to fractured emerald dust on small rounds. It happens in a split second followed by OH (insert cuss word here)!

If your setting small stones say under 2.5 mm you can just use ball burs and not worry about setting bur or as Silverchip suggests

sometimes I drill a small pilot hole for the burr to follow

Silverchip pretty much summed it up for you in a nutshell.
you can always do a couple in brass to get a feel for it. little easier to work with
then try doing it in steel. One thing is try using lubricant with the burs it gives them longer life and keeps them sharper longer.
Also when you do the drilling, try not to push to hard... let the Bur do the work and not you pressure on the Bur , you will find that your burs will last much longer.

I open up the hole with a ball or bud bur depending on the size of the stone. I use the setting bur only as a final set to define the seat/bearing for the stone.

Reason...ball and bud burs are much less expensive than setting burs AND they do a better job of hogging out the bulk of the metal.

As for holes, I usually start with a .7 or .8mm drill then open up the hole with a larger drill. As a good rule of thumb the hole should be 40-60% of the diameter of the stone. You want the hole large enough that it facilitates easy cleaning of the back of the stone but not so huge that the structural integrity of the piece is weakened.

Did you buy a setting burr or a diamond burr? A picture would help. Rio Grande sells quality tools. I have a suspicion you bought the wrong burr for the job.

A good quality set of Setting burs should cut cleanly provided you have pre-drilled, and are using lubrication. The suggestion of drilling a pilot hole followed by bud bur and lastly setting bur to cut the seat is spot on. This is the method I've used for 30 years. If I have a 3mm stone, I cut a pilot hole about 1.5-2mm. This is only if I'm not compromising the integrity of the support structure of the piece by doing so. If you need more strength, then a smaller pilot/clean out hole followed by a bud bur is the way to go. I use the setting bur to sneak up on the final seat size. If you use the setting bur to try and remove too much material, you'll only shorten the life of the bur and as you've already seen, you'll get material building up on the edge of the seat.
Next thing to remember is that there are a million different ways to go about it, and every situation might demand a different technique. Stone setting is an art best learned by working with an experienced setter. A video can get you started but there are just too many little secrets to the task that are best conveyed with hands on instruction. This forum is the next best thing!
Layne

Burrs are working great now! I slowed the speed. Thanks to everyone.