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I've just started drilling some 5mm holes with a diamond core drill bit. The holes are great but how the heck do I get the little glass plugs out of the bit?
There are slots cut into the side of the bit so I assume you should be able to slip something in there to pop the glass out. However I've already managed to stab my finger with my x-acto knife so figured I'd better get some expert advice. I realize I've got about three plugs in the bit since I can hear them when I shake it.

When you figure it out, let me know.

The only way I've been able to successfully get them out is to heat up the entire bit and dunk it in icewater, which fractures the glass and shake out the pieces.

You have to drill those out with smaller 2mm drills they come right out, but then you need to clear the 2mm drill bit so i guess that means 1mm bits. - haha

Cynthia is right, let me know if you figure it out.

I either A) push the plug out from the side slots using the post of an old 2mm or so drill bit ( one you don't mind getting bent in the process), or, B) take the core drill bit out of the drill press and push the plug out with a 3mm bead mandrel. sometimes using the bead mandrel requires a few taps with a hammer to loosen the glass plug.
BTW: those glass plugs make excellent accent pieces on other projects!

DOLORES

I use a piece of 10 gauge nichrome wire I happen to have kicking around. I push it through. You have to do it after every hole is drilled. The smallest drill I use happens to be 6mm, but it works well for me. I am assuming your drill bit has a hollow core, as mine do.

bead mandril pushed out from behind after every hole.pita. next time i have a bunch of holes to drill i am going to line up a helper. i will use 3 or 4 drill bits and the helper will be poking out the plugs while i drill. r.

Thanks everyone. Problem is, one end of my bit is solid, so there's no pushing the plug out. Secondly, the slits in the side are small enough that I can fit my x-acto blade in, but nothing else.

I guess I'll try Cynthia's heat and ice method first, and then perhaps drilling into the plug next.

It's a pretty stupid design, IMO.

Order them from these guys. At 35 cents each they are virtually disposable.

http://thk.hk/onlinestore_details.php?id=24

I buy all kinds of core bits from them.

Rick ..Have you ever tried the larger bits (3" or 4") from this supplier??
Don

the biggest ones I've bought are 60,80,100 and 120 mm from them.

These bits are not the absolute best quality but they are all worth the money.

They are 1/10 or less the prices of others out there.

Rick, you have so made my year!! I have spent hordes of time and money on overpriced and often underperforming discs and drill bits. In general, the economy ones last longer and are more durable. 60 grit flat lap discs, oh yeah, I'm all over that!

DOLORES

Hmm... I buy the 1.4mm diamond coated triple ripple drill bits from Abrasive Technology for five times the cost of THK 1.5 mm diamond coated twist bits. Has anyone tried their small twist bits?

Rick Wilton wrote:Order them from these guys. At 35 cents each they are virtually disposable.

http://thk.hk/onlinestore_details.php?id=24

I buy all kinds of core bits from them.

Rick, saved this site as a favorite BIG TIME.

I'm going to try scoring the underside of my cut once the circle is defined when using bigger bits to see if I can break the glass plug by tapping with punch and hammer. Will be testing this in the next day or two.

Michele, The triple ripple bits work better, less break out on the backs means fewer pieces broken. The price difference works out to less waste of your pieces. I switched- broken pieces are dollars wasted, especially at the last step before sending the work out.

Wonder if it would help if you put the bit through an ultrasonic jewelry cleaner?

I use a thin finish nail and put it through the side slots and tap it downwards with a small hammer. You could also just try a punch or nail set. Hit it in the center and break it (maybe score it first). Have to take the bit out of the press to do that.

Before Drilling the glass, I drill through a thick kitchen sponge so the sponge fills part of the core. Then I dip the sponge into water and that helps to keep the core drill wet when drilling the glass. You can keep on dipping the sponge filled drill into water until the job is finished. The glass then can pop out of the drill bit easier.

Rick

I bought some of these once, and the shafts are so short that they don't work in my tripod glass drill. I tried to find a bit extender, but they are larger than an American bit extender, so they sit in my drawer, unusable, except in the regular drill press, which I seldom use.

Rick Wilton wrote:Order them from these guys. At 35 cents each they are virtually disposable.

http://thk.hk/onlinestore_details.php?id=24

I buy all kinds of core bits from them.

THK is also sold by Lau on Ebay (they have been mentioned on Warm Glass in the past). I have bought a lot of bits from them and the large core ones work well. The largest I have is 60mm. I also use the 2mm. My most recent batch had many without sufficient grit on the ends and when I tried to drill, they skated (I always test a new bit on scrap glass first). That said, when one works - it works great - over 100 holes with one 2 mm bit.

That's too bad Bert, I've modified a regular drill press to have a MUCH bigger throat. I don't usually need to drill anything more than 3-4 inches from the edge but I can drill 12+"

Not as useful as a tripod drill but they run $700+

Bert Weiss wrote:Rick

I bought some of these once, and the shafts are so short that they don't work in my tripod glass drill. I tried to find a bit extender, but they are larger than an American bit extender, so they sit in my drawer, unusable, except in the regular drill press, which I seldom use.