When drilling a hole in a cabochon or glass or what-have-you, an
operation usually performed with the object standing in water, how
does one avoid being electrocuted? I have purchased a used
Foredome flex shaft, but haven't tried this yet due to caution. And
yet I know that drilling in shallow, standing water is a standard
with flex shaft tools in general, the handpiece is not in any way
part of any electric circuit. Only the motor and foot pedal control
are. Getting the handpiece wet has no impact on this, and offers no
risk of electric shock. The situation might be different with some
types of powered handpieces where the motor is part of the handpiece
itself, such as Dremel tools or some of the micromotor types of
tools. But even there, it’s likely safe, since these tools are
carefully designed to isolate electric circuits from the user,
whether or not there is water involved. After all, you’re holding the
tool in your hand, even if dry, so if there were any possibility of
shock when wet, there’d also be some risk while dry, so these tools
are double insulated, with exposed parts electrically isolated, and
usually non-conductive. And with the micro motor types of tools, many
of them operate the handpiece itself on low voltage (safe) even if
the control plugs into household wall current.
By the way, the insulation issues are not confined to jewelers
tools. Normal power tools, drills, saws, etc, are expected to be safe
to use in all sorts of conditions, including outdoor construction,
where rain can be occasionally a factor. Again, the tools are
designed to remain safe even if water is involved. This is part of
what is involved when tool manufacturers obtain UL certification for
And finally, you should keep in mind that water, by itself, is not
actually all that good an electrical conductor. Salt water, or water
with other current carrying ions dissolved in it, is another matter.
But when you’re drilling “under water”, no doubt you’re just using
tap water, which starts out clean enough, so isn’t very conductive.
And, it’s also confined to a small container, so it is isolated from
the environs. The real danger of shock with water is when it’s in
contact with “ground”, and can then make the electrical path from a
voltage source back to ground, more likely. Thus, don’t stand in a
puddle and handle live wires, since your wet feet are not well
insulated from ground. But this type of situation is unlikely with
properly designed and undamaged electrical tools, even those with a
motor in your hand and plugged into the wall (like an electric
drill), because of the multiple layer insulation built in.
But as I said, your flex shaft tool is not even in this catagory.
There’s no electric voltage or possible voltage at the handpiece. Run
the thing with the handpiece under water if you want. I don’t
recommend it, as this likely will allow corrosion of the handpiece,
but you’d not be risking shock to do it.
In drilling, set it up so the drill end itself is running under
water, while the chuck and handpiece stays above water and thus,
mostly dry. You’re not taking any risks to do this.