Every now and then on this forum, someone indicates they no longer
use hanging motors. Would you all discuss the differences between
two alternatives that are sometimes mentioned, micromotors and the
First, the airgraver (or it’s competitors, such as the GRS engraving
systems) is not an alternative for a flex shaft motor in most cases.
It’s an engraving handpiece used with engraving tools, gravers, etc.
It differs from ordinary inexpensive gravers in that it’s the handle
to hold the gravers, but incorporates an impact mechanism, a little
like a miniature air hammer or hammer handpiece, used to help push a
graver through the metal without your hand having to actually push
the graver. Very handy if you do engraving, or stone setting work or
other tasks traditionally done with gravers. But the rotary tools
used in flex shaft handpieces/motors, are not used with the
Engravers often need to do very delicate removal of background
areas, and while this can be done the traditional way, with gravers,
especially flat ones, it’s often faster to do it with tiny rotary
tools. Because of the small size, these are often carbide, and work
best at high speeds. Micromotors are ideal for this.
There are also air driven handpieces, much like the very high
pitched whining sounding ones your dentist may use, that are even
more specific to this type of work.
Micromotors are somewhat similar in function to flex shafts, but
with a difference. Flex shaft motors work very well at quite low
speeds, and generally deliver a lot of torque. This makes them useful
where a degree of power is needed, driving larger burs or sanding
attachments, and more. They also work at high speeds, but most flex
shaft motors are limited to well under 20 thousand RPM. Thats fast,
but not really high speed. Micromotors, by contrast, generally can go
up to 35 thousand RPM or more, and at thise high speeds, bits and
cutters operate with noticably less drag, catching on the work less.
Some tools, like carbide cutters, really like being operated at these
speeds, as they chip less and cut better. But most micromotors (there
are exceptions) have substantially less power and torque, so larger
diameter tools don’t work quite as well. Also, the feel of the
micromotors is different in the hand, since you only have a light
coiled electric cord coming from the handpiece, instead of that
sometimes awkward flex shaft tied to the actual motor. With
micromotors, you also have pretty much just the one handpiece, though
some brands offer several types, including a hammer handpiece on the
badeco brand and a couple others. With flex shafts, the various
handpieces are generally interchangeable, and there are pages and
pages of different types in the catalogs. Finally, the cost.
Micromotors generally cost anywhere from around 400 to a couple
thousand, though there are a couple really basic and cheap lighter
duty Korean ones sold for around 150 to 200. (I have a couple of
these, and don’t regret them at all. Not high powered, limited to
only about 35K RPM, but they work reasonably well). On the other
hand, you can get cheap basic Flex shafts for a couple hundred
dollars. Adding quick change handpieces can quickly raise the cost of
your system, but they’re still much less expensive than the
micromotors. Generally, I’d expect the flex shaft machines to be
somewhat more durable too, in the degree to which they withstand
somewhat rough use and abuse.
Bottom line is that all three types of tool are distinct. The air
graver or GRS graver tools are distinctly difference, with different
uses. The flex shafts and micromotors overlap a lot. The big
difference is the micromotors are at home with more delicate but
higher precision uses at higher speeds, which the flex shafts are
slower, more powerful, with less precision (though that depends a
lot on the handpiece, more than anything else.)
If you’re just getting into jewelry, that flex shaft is almost one
of the beginner essentials. Almost. Not quite like basic hand tools,
but your capabilities will expand a lot once you have one.
If you’re exploring engraving, you can learn the old time way, with
manual push gravers. They work. But they can take a good bit of time
to master, and using them until you really are a master of the
things, will be a lot slower. The power gravers like airgraver will
cut your learning curve to a fraction of the time, so you spend your
time learning what the cuts look like, how to design, and that sort
of aesthetic aspects of engraving, rather than building up obscure
muscles in your hand, without which you’ll never quite control a
The micromotors aren’t essential to anything. But like any
semi-luxury tools, they’re really nice to use when they’re the right
tool, make some things work better or with more control, solve some
problems with the flex shafts, and make a great addition to the
workbench. Some specialists, especially diamond setters doing things
like micropave under a scope, (Or for that matter, dental techs
making crowns and bridges often using smaller precision abrasives,
diamond tools, etc,) may well use only their micromotors, while
others will use both.
That’s my two cents, anyway. Hope it helps.