Hi Carol,
Does anyone know what the going rate is for drilling holes in
stone? I've been asked if I'd be interested in drilling some holes
in a few cabs for someone and have no idea what a fair price would be
for it.
You don’t need an ultrasonic setup, but you do need a light touch and
some familiarity with the materials you intend to drill. Asking how
much to charge per hole may be tantamount to asking how much a
diamond should cost, as there are quite a few variables to consider,
not least of which is how much you charge for your time. The next
questions need to be as follows:
- How many cabs will you be drilling?
- What size are they? And (again),
- What are they made of?
For example, a Nephrite or Jadeite cab might take you six to ten
minutes (or longer) to drill through, while a Turquoise, Variscite,
Sodalite, Rhodochrosite, Lapis or Howlite could be over and done in
thirty seconds, or so. The four or five most crucial things to
remember, when drilling stones of any type, are to keep the speeds
relatively low, the coolant levels high, to use a slow
up-and-down-pecking motion (rather than trying to force the bur
through faster, out of frustration), and to prime both surfaces –
the entry and exit – with a small ball bur, before approaching them
with the drill bit, itself.
If you’d like to keep the stones intact, the speeds and coolant will
be your most confounding hurdles, since erring on either can
potentially leave you with an unhappy client and an unwelcome hole in
your monthly budget. To overcome the first, set your flex-shaft or
Dremel moto-tool on its slowest speed, or keep the bur at an rpm at
which you can still see a slight shine off of its business end. For
the coolant level, you can make the same jig I did, out of sheet
brass or copper, which is basically a flat-bottomed bezel cup on
steroids: a piece of 20 gauge sheet about 4x3", with a
3x2.5x0.5-0.75" vertical walled oval or rectangular well in the
center. This well should hold the coolant (slightly soapy water works
nicely)just slightly deeper than your workpiece is tall, so there’s
no way for your stone to overheat. For most stones, I’d recommend
using dop wax (or shellac) to hold your stones in place, so you can
go from one to the next, to the next, wihout having to stop
andreposition things. (That 1/2" horizontal flange – around the
vertical wall – is used for clamping the apparatus to your
workbench or drill press base, so it doesn’t “walk” during the
drilling operation. Hope this has been helpful to you!
All the best,
Doug
Douglas Turet, G.J.,
Turet Design, LLC
P.O. Box
242
Avon, MA 02322-0242
Tel: (508) 586-5690
Fax: (508) 586-5677