How to drill gems?

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Originally Posted by Sliding Head

BTW that project took me about 4 months and was canned because of the tool wear and the taper in the hole which used all of the hole tolerance in about twenty holes. Even though I got tool life (it was still cutting up to 80 holes) the hole geometry was poor. The ultrasonics and laser methods weren't acceptable at the time.

Good luck
D

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So Boyan the Lesson I took from that excellent post was DONT BOTHER because your DIY machine and Spindle just aint going to cut the mustard. . . This is high precision work that requires high precision machine and not just good tooling.!

If the holes were bigger I'd have suggested the old low speed tubing & abrasive paste method, maybe sections of hypodermic needle & diamond paste would work but you'd need a system of regularly lifting & then reapplying drilling pressure

Luckily precision is not the aim here but quantity. The holes have to be on a precise place, could be slightly tapered and sizes could slightly vary. This is not drilling rubies for watches. Just jewelry.


I spoke with my friend and he said 1.2 to 1.5mm holes are ok. So i will forget for holes below 1.2mm. So seems a china spindle with VFD will work right and have acceptable speed. May be even better will be one of the small Dc spindles. The question here is if that should be driven down by motor, lever or just counterbalanced and let its weight drill slowly the stone.

Its possible that weight or lever with straight down feed will both result in a hole jammed up with powder and shed diamond cutting debris with significant tool life reduction, if you combined one of those two with table moves to cut 1.5 holes with 1.2 cutters and air to clear dust you might be onto a winner

- Nick