You’ll enjoy using a flex shaft after you get it; you’ll wonder
how you ever got along without one. From your address it looks as
though you may be located down under. If that’s the case some of
this info may not be of any value.
Some things to consider when selecting a general purpose flex
shaft are: the top speed, horsepower, torque (especially at low
speeds), the number of different hand pieces available for it &
it’s repairability (repair part availability). In the US there
are 2 main mfgrs of flex shafts, Foredom & Pfingst. Both make
several models & their hand pieces are generally interchangeable
between brands. There are also some import brands that are knock
offs of these 2. You won’t go wrong with either brand. There are
several mfgrs of hand pieces also. Generally speaking unless
specifically indicated, all mfgrs hand pieces will work with any
flexshaft power unit.
Generally all flex shaft motors will provide sufficient power
when running at close to full speed. The real test of a power
unit is at low speed, does it provide enough power to do the job
when running slow. The Foredom model ‘R’ has a feedback loop
built in that provides for full power at slow speed. It’s speed
range is listed at 0- 20,000 rpm.
Equally as important as the power unit is the hand piece. That’s
the part you’ll be in intimate contact with for many hours. It
should feel comfortable in your hand for long periods of time, be
vibration free, run true (no wobble of the installed bits) &
provide for quick & easy bit changes. There are several types of
hand pieces for holding rotary bits. The most basic is the key
operated Jacob’s chuck similar to the ones used on many drill
presses. It can accommodate any diameter bit from size 0-5/32
inch (4 mm). The collet type hand piece has several different
size (usually 1/32 - 5/32 in) changeable collets that hold the
bit. The quick change hand piece has a lever that is operated to
open & close the collet. Generally the collet will only
accommodate 3/32 in. diameter tool bits.
Each type has some advantages & disadvantages. The Jacob’s chuck
will accommodate the widest range of tool sizes & there are
specialized tools made by other mfgrs (Allset, Koil Kutter, etc.)
that attach to the Jacob’s chuck hand piece. The disadvantage of
the Jacob’s chuck is the time it takes to loosen & tighten the
chuck when changing bits. If many bit changes are required this
time can add up.
With the collet type, the bit tends to run more true than with
the Jacob’s chuck. Disadvantages: you’re limited to bits that fit
the collet currently installed. A wrench is also required to
tighten/loosen the collet. The collet must be changed to
accommodate a different diameter bit. Again, time required for
bit changes can add up.
The quick change has a lever that is operated to open/close the
collet for bit changes. Some hand pieces allow opening/closing
the collet before the flex shaft has come to a complete stop. The
advantage of the quick change is the time saved when making bit
changes. The disadvantage is the collet is usually limited to
3/32 in diameter bits. This is not all bad, since the majority of
bits, burrs, etc. are furnished with 3/32 in diameter shanks.
There are adapters available that go from 3/32 to other sizes.
If you only get 1 hand piece, go with the Jacob’s chuck type (
Foredom #30 or equal). If you can afford a 2nd one, I’d also get
a quick change.
One nice thing about Foredom, Pfingst & equivalent flex shafts;
The hand pieces can be removed & installed from the flex shaft
with out the use of any tools. The hand piece is pulled off &
pushed on the flex shaft. They’re retained on the flex shaft by a
spring loaded ball riding in a grove in the flex shaft.
I use a Foredom ‘R’, # 30, a quick change & a hammer hand piece
in my shop.
Hope this helps.