Dremel 398 Instructions page 23

• paring knife hand grip for rough work (grinding)
• 2 hand golf grip ideal for when you need to keep the tool parallel to the work surface,I.e. using a cut-off wheel
APPLICATION ADVICE
• Always practice on a piece of scrap material first to choose the right accessory and determine the optimum
working speed
• Do not apply to much pressure on the tool; let the speed do the work for you
• Use only accessories that are recommended by the manufacturer for your model.
SPEED
• Electronic Feedback Circuitry (EFC)
Your tool is equipped with a internal electronic feedback system that provides a "soft start", which will reduce the
stresses that occur from a high torque start. The system also helps to keep the pre-selected rotating speed
virtually constant between no-load and load conditions.
• Digital Speed Selector Switch
Your rotary tool features a digital speed selector switch which displays an L.C.D. reading of the tool's RPM. The
speed can be selected from 5,000 RPM to 30,000 RPM in 1,000 RPM increments by simply depressing the
positive or negative buttons on the switch.
TO TURN TOOL "ON": slide ON/OFF switch "C" to the "ON" position.
TO TURN TOOL "OFF": slide ON/OFF switch "C" to the "OFF" position.
TO INCREASE SPEED: depress button "E" with + sign.
TO DECREASE SPEED: depress button "F" with - sign.
Some rules of thumb in regard to speed:
1. Plastic and materials that melt at low temperatures should be cut at low speeds.
2. Polishing, buffing, and cleaning with a wire brush must be done at speeds below 15,000 RPM to prevent
damage to the brush.
3. Wood should be cut at high speed.
4. Iron or steel should be cut at top speed if using tungsten carbide accessory, but at lower speeds if using high
speed steel cutters. If a high speed steel cutter starts to chatter-this normally means it is running to 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.
To aid you in determining the optimum operational speed for different materials and different accessories, we have
constructed a series of tables that appear on diagram
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 happens 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 slightly to get the optimum working speed.
Increasing the pressure on the tool is not the answer when it is not cutting as you think it should. Perhaps you
should be using a different cutter, and perhaps an adjustment in speed would solve the problem. But leaning on
the tool seldom helps.
MAINTENANCE AND REPAIR
• Keep tool and cord clean (some household cleaning products and solvents can damage plastic parts; these
products include among others benzine, trichloroethelene, chloride, amonium
• Excessive sparking mostly indicates worn-out carbon brushes
• In case of an electrical or mechanical defect, hand in tool at one the DREMEL Service Stations for repair
(addresses are listed on the service diagram supplied with the tool)
GB
. By referring to these tables, you can discover the
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