what do you use to drill holes in fused glass cabochons?

[terrylynn124]

I recently made several dichroic cabochons, most of which are comprised of three layers of glass. I had (past tense) some very tiny drill bits (less than 2mm thick) that I tried (yes, they worked on two pieces) until I smoked through several of them. So I went to the store and found some diamond bits and tried them. They worked much better, but each bit only lasted long enough to drill through one, maybe two cabochons before becoming dull and useless. Due to the variety of head shapes in each package, I can only use two out of the six bits, which makes it quite obvious that this is NOT an economical means of drilling holes in glass. Can anyone tell me what I'm doing wrong here? I drill with my glass slightly under cold water and I proceed at a slow pace. Am I using the wrong bits? Are three layers of glass too much? Thanks.

[gwacie]

1) you need to be drilling wet (in a small amount of water) or you will destroy your bits in short order. Some folks use a plastic container with a little water and a sponge as the drilling platform - you rig something up. Don't electrocute yourself. If you do some research you can probably find a photo. Sounds like you are doing this.

2) you need to let the bit do the work, don't press hard on it, and allow water to seep into the hole as you work. You may be pressing too hard.

3) Consider either prefusing the hole in OR routing the edges for wire wrap instead of drilling holes if you want thick cabs.

4) get good diamond bits - the cheaper ones don't last as long.

Good luck.

[rainygrrl]

Are you moving the drill in and out so the pieces of glass get flushed out?

Someone recommended "triple ripple" bits to me:
Crystalite Triple Ripple Drills Twice the life and cutting rate of standard diamond drills. This music wire diamond drill has three flutes to allow cuttings to flush away and decreases frontal contact and drag. As the edges wear, fresh diamond in the flutes maintains the cutting action. Recommended RPM - 5,000 to 20,000.

Or as Bethany mentioned you can pre-drill with a core-style drill bit before fusing. In this case I am pretty sure that 3 layers fully fused would close up the hole made by a 1/4-inch bit. But you could fuse, then drill, then fire polish...

Hope this helps!

[SteveWright]

We use triple ripple bits. The piece has to be submerged in cool water and the bit retracted every few seconds to prevent smoking the bit.

Experiment with some 1/8th inch fiber paper, cut into 1/8th inch wide strips. We cut the middle layer of glass into two pieces, leaving a gap near the top, where you want the hole. Fill the gap with the fiber paper.

Steve

[Emiko]

Are you moving the drill in and out so the pieces of glass get flushed out?

No. You use a diamond core drill. With a core drill glass has a way to be flushed out. To start, tilt the drill a little and dig a little by the edge, then start a vertical hole. Otherwise the dril slipps around on the glass surface. Practice first on a scrap piece.

[terrylynn124]

Thanks for the help. I think that I wasn't moving to bit back up enough so that fresh water could flush the hole out. I will try it again using your suggestions.

[susiekline]

I've had great luck drilling holes in my cabs (usually two layers of glass) with my drill press and carbide glass bits from Harbor Freight. They sell a multi-sized bit pack for a great price. I had no luck at all with the diamond bits.

I use a small bowl and a sponge, fill with water, and drill away.