Enlarging holes in pearls...

[pearlescence]

You'll struggle to hold pearls in a vice without scratching them. finger and thumb I'm afraid (and you'll get the hang after you've drilled your thumb a few times!)
I think I would try for big knots to hold the 1mm hole beads rather than make the pearls bigger.

[danny.p]

How clever!

I tried expanding them with a hot needle, but this seems better.

Gonna try it out definitely!

[uptondownton]

Old thread but handy to know a possible solution -

A bead reamer is what you need. They come in different diameters, manual ones that you twist or battery operated ones. A "bead reamer" search will bring up many results.

[pearlescence]

No you don't. They take hours, you will get RSA and the tip will snap in the hole.
As I said above. New drill bit and ordinary drill on full power and fastest speed possible.
I spend my days drilling pearls for a living

[uptondownton]

No you don't. They take hours, you will get RSA and the tip will snap in the hole.
As I said above. New drill bit and ordinary drill on full power and fastest speed possible.
I spend my days drilling pearls for a living

It all depends on the ratio of difference between the original pearl hole and the desired size of hole, obviously if it is a great difference, a bead reamer will not be adequate or a quick fix. Bead reamers are for smallish adjustments or unblocking poorly drilled holes or for pearl dust build up left over from the original drilling process that can block the hole.

Anyway, I hope you found the correct answer for your specific problem.

[pearlescence]

Nope. Reamers are never the answer
A few drills in 0.1mm increments are.