Dentist drill

Hi Gwaai, I’m not really familiar with your type of dentisis drills
but I can tell you that on Brush-type electric motors it is fairly
common to see sparks at the brushes. The smell is most often
associated with ozone that is produced by the electric sparks in an
oxygen atmosphere like air. The tool that shows larger sparks may be
in need of new brushes. If the brushes are worn down it can make the
motor tend to overheat and this too can cause an odor. Please
remember to keep safety in mind with these tools. Those sparks are
quite able to ignite flammable fumes from solvents or gasses from
torches. Make sure there are no concentrations of these in your work
area by ensuring proper ventilation.

You may need to contact the manufacturer to get new brushes for
these tools. I advise folks to always have an extra set of brushes
on hand. Breakdowns in the middle of a project can really disrupt
the creative flow. I hope this helps you out somewhat. There are
lots of knowledgable people here at Orchid that probably know more
about this than I do.

Mike

It sounds to me as though the contacts in the motor are just about
shot. What you’re smelling is ozone - a really good reason not to
run the drill in an enclosed space for long. The best thing you can
do to salvage this equipment is to contact the manufacturer and find
out A: if the contacts are replaceable, and B: if they still
manufacture the necessary contacts or have any in stock. If you’re
not up to the job of replacing the contacts (it’s fiddly and
frustrating, but if you weren’t into that you wouldn’t need a
dentist’s drill), they might be willing to replace them for a fee.
Make sure you have the model number handy when you call.

-Michael Balls

With older motors it can be difficult or expensive to find
replacement brushes. My 30 year old unimat lathes brushes list for
about $50 + S&H. A few messy minutes with a file and Foredom flex
shaft brushes fit fine.

Jeff
Demand Designs
Analog/Digital Modelling & Goldsmithing
http://www.aztec-net.com/~jdemand