Diamond Cut Drill Bits

[micpru]

I've been using diamond drill bits with my hand held dremel for drilling 2mm holes in glass.  I drill with the glass resting on a piece of wood and in a dish of water, the glass is always under water.

Recently I have been finding that the drill bits don't last very long as while drilling there is a glow and a bit of a spark and then the drill bit goes blunt at the end and cant be used anymore.  My last one lasted 3 holes.

Any ideas on what I might be doing wrong?  x

[MangoBeads]

Strange I'm not sure what the problem could be - the glass does nt need to be under water but there should be a constant water feed into the drilling area from the top. Diamond drills do vary you could try using a sintered one they are more expensive but last longer  - Eternal Tools have a good selection we use them and they last for ever and we drill a lot

[micpru]

Lookingt the eternal tools site I think I might be trying to be too speedy and applying too much pressure so the diamond bits fall off. Will try again. Thanks x

[DragonArtGlass]

Might be worth trying grinder coolant in the water.

http://www.tempsfordstainedglass.co.uk/acatalog/info_GCOOL_.html

[julieHB]

Lookingt the eternal tools site I think I might be trying to be too speedy and applying too much pressure so the diamond bits fall off. Will try again. Thanks x

I think you are right - with as small diameters as 2mm you can drill at quite a high speed, but put almost no pressure on the dremel (the weight of it is enough). Also, I lift the drill bit up quite often to allow new, colder water to enter the hole.

From what I have found it is a lot more efficient to use a core drill bit instead of a solid one. Just remember to remove the little glass piece stuck in the bit after every hole you make.