Dremel 4200 Operating/Safety Instructions Manual page 12

The speed of Rotary Tool is controlled by
setting this dial on the housing (Fig. 8).
Settings for Approximate Revolutions.
VARIABLE SPEED
DIAL
Switch Setting
5
*10
15
20
25
30
35
* Wire Brush Setting.
Needs for Slower Speeds
Certain materials, however, (some plastics and
precious metals, for ex ample) require a
relatively slow speed because at high speed
the friction of the accessory generates heat
and may cause damage to the material.
Slow speeds (15,000 RPM or less) usually are
best for polishing operations employing the felt
polishing ac ces sories. They may also be best
for working on deli cate projects as "eggery"
work, delicate wood carving and fragile model
parts. All brushing applications require
lower speeds to avoid wire discharge from
the holder.
Higher speeds are better for carving, cutting,
routing, shaping, cutting dadoes or rabbets in
wood.
Hardwoods, metals and glass require high
speed operation, and drilling should also be
done at high speeds.
Many applications and accessories in our line
will provide the best performance at full speed,
but for certain materials, applications, and
Use only Dremel
FIG. 8
Speed Range
15,000-7,000 RPM
17,000-10,000 RPM
13,000-17,000 RPM
18,000-23,000 RPM
23,000-27,000 RPM
28,000-32,000 RPM
33,000-35,000 RPM
® , high-performance accessories.
accessories, you need slower speeds, which is
the reason our variable speed models are
available.
To aid you in determining the optimum
operational speed for differ ent materials and
different accessories, we have construct ed a
series of tables that appear on page 21, 22, 23
and 24. By referring to these tables, you can
discover the recommended speeds for each
type of accessory. Look these tables over and
become familiar with them.
Ultimately, the best way to determine the
correct speed for work on any material is to
practice for a few minutes on a piece of scrap,
even after referring to the chart. You can
quickly learn that a slower or faster speed is
more effective just by observing what hap pens
as you make a pass or two at different speeds.
When working with plastic, for example, start at
a slow rate of speed and increase the speed
until you observe that the plastic is melting at
the point of contact. Then reduce the speed
slight ly to get the optimum working speed.
Some rules of thumb in regard to speed:
1. Plastic and other materials that melt at low
temperatures should be cut at low speeds.
2. Polishing, buffing and cleaning with any type
of bristle brush must be done at speeds not
greater than 15,000 RPM to prevent damage
to the brush from bristles flying toward
operator.
3. Wood should be cut at high speed.
4. Iron or steel should be cut at high speed. If a
high speed steel cutter starts to chatter — this
normally means it is running too slow.
5. Aluminum, copper alloys, lead alloys, zinc
alloys and tin may be cut at various speeds,
depending on the type of cutting being done.
Use paraffin or other suitable lubricant on the
cutter to prevent the cut material from adhering
to the cutter teeth.
Increasing the pressure on the tool is not the
answer when it is not performing as you think it
should. Perhaps you should be using a
different accessory, and perhaps an
adjustment in speed would solve the problem.
Leaning on the tool does not help.
Let speed do the work!
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