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Start the tool before applying to work and let the tool come to full speed before contacting the workpiece. Lift the tool from the work before releasing the switch. DO NOT turn the

switch “ON” and “OFF” while the tool is under load; this will greatly decrease the switch life.

ELECTRONIC FEEDBACK

Your tool is equipped with an 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 preselected speed virtually constant between no-load and load conditions.

VARIABLE SPEED DIAL

This tool is equipped with a variable speed dial. The speed may be controlled during

operation by presetting the dial in any one of six positions (Fig. 1).

Dial Setting

RPM

1

750

2

1200

3

1600

4

2000

5

2400

6

3000

Sanding Operations

SELECTING SANDING DISC

Sanding discs are made of extremely hard and sharp aluminum oxide grits, phenol-resin bonded to a sturdy fiber backing for fast heavy-duty service and long life. The discs vary as to size and spacing of the abrasive grits. OPEN COAT (type H) — used for soft materials and on paint or varnish. CLOSED COAT (type K) —used for metal, hardwood, stone, marble and other materials.

Sanding discs range in grit from 16 (very coarse) to 180 (very fine). To obtain best results, select sanding discs carefully. Many jobs require the use of several grit sizes and

at times both “open coat and closed coat” discs are required to get the job done faster. See chart for application examples.

Operation: Refinishing painted wood or metal surfaces.

REMARKS

GRIT

 

 

To remove paint and to smooth

Coarse

surface irregularities.

16-24-30

 

 

To smooth

Medium

the rough sanding.

36-50-80

To remove scratches left by

Fine

previous discs.

100-120

 

 

To smooth surfaces for painting,

Very Fine

polishing or waxing.

150-180

 

 

SANDING TIPS

For best results, tilt the Disc Sander at a 10° to 15° angle while sanding so that only about 1"

of the surface around the edge of the disc contacts the work.

If the disc (accessory) is held flat or the back edge of the disc comes in contact with the work, a violent thrust to the side may result.

If sander is tilted too much, sanding action will be too great and a rough cut surface or gouging and snagging will result.

Guide the Disc Sander with crosswise strokes. Be careful not to hold the sander in one spot too long. Do not use a circular motion, as this makes swirl marks. Test before use on scrap stock.

Do not force or apply pressure when sanding. Use only the weight of the tool for pressure. Excess pressure actually slows the tool down. If faster stock removal is desired, change to a coarser grit disc.

Remove gummy paint from metal with an “open coat” disc. Sand until sparks start to appear, then stop and change to a “closed coat” disc to remove any remaining paint.

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Bosch Power Tools GP712VS manual Sanding Operations