How a belt sander removes wood
The belt runs continuously in one direction, so every grain cuts in a straight line, along the board when the sander is moved with the grain. The platen — the flat plate behind the belt between the drums — sets the contact area and keeps it flat. That straight, continuous cut is why belt sanders are used to level glued-up panels and take off stock quickly, and why they are not the machine for final smoothing: the finer stages are done with a random orbital or sheet sander and the sanding sequence.
Belt size and speed
| Model | Belt | Belt speed | Notes |
|---|---|---|---|
| Makita 9403 (handheld) | 4 × 24 in (100 × 610 mm) | 500 m (1,640 ft)/min | Single speed |
| Makita 9903 (handheld) | 3 × 21 in (76 × 533 mm) | 210–440 m (690–1,440 ft)/min | Variable speed |
| RIKON 50-112 (bench) | 4 × 36 in | 1,900 SFPM | With a 6 in disc at 3,450 RPM |
| RIKON 50-122 (bench) | 6 × 48 in | 1,836 FPM, no load | With a 10 in disc at 2,510 RPM |
From Makita's and RIKON's manuals. Belt speeds are surface speeds; the disc figures are rotational speeds and are not comparable with them.
- Belt size sets the platen area and the belts you must buy: the maker's manual names the size, and RIKON says to use belts and discs of the width and length the manufacturer recommends.
- Belt speed is a surface speed, in feet or metres per minute. A variable-speed machine such as Makita's 9903 sets the belt speed with a dial; a single-speed one such as the 9403 runs at one speed.
Equipment notePaid link
3 x 21-in variable-speed belt sander
Makita 9903
The variable-speed sander this section quotes: Makita's 9903, a 3 × 21 in belt at 690–1,440 ft/min, by its manual.
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Handling a handheld belt sander
- Both hands. Makita's manual says to hold the tool firmly with both hands.
- Keep the platen flat. Tipping the machine puts the belt's edge or a drum into the work and digs a hollow; keep it moving and flat.
- Tracking. The belt must run centred on the drums. Makita says to adjust tracking with the knob while the belt is running.
- Power off before adjusting. Makita says to unplug the tool before making adjustments or changing belts.
- Dust bag. Makita says to empty its bag when it is about half full, so it keeps collecting. A bag is not a substitute for exhaust: OSHA's preferred control is ventilation at the source.
- Secure the work. A belt sander pulls the work in the belt's direction; clamp the work down — see clamps and workbenches.
Bench belt and combination sanders
A bench machine reverses the arrangement: the belt is fixed and the work is brought to it on a table. RIKON's manuals give the rules that come with that: fasten the sander to a firm surface, keep no more than 1/16 in between the abrasive and its tables, feed work into the abrasive on its downward direction so it is pressed against the table, and disconnect power before changing belts or discs. Choosing one is covered in benchtop sanders, and handheld models in choosing a belt sander.
Using a belt sander
- Belt of the size the manual names, fitted in its direction of travel
- Tracking set with the belt running
- The work clamped, or the bench machine fastened down
- Both hands holding a handheld machine, platen flat, always moving
- No more than 1/16 in between abrasive and table on a bench machine
- Power disconnected before adjustments or belt changes
Sources
Belt sizes and speeds are each maker's for the model named; Makita states speed in m/min and ft/min, RIKON in SFPM or FPM, both no-load where stated. No feed rate is given because no maker reviewed publishes one.
- 1.
Belt Sander 9403 / 9921, Instruction Manual. Makita.
Used for: The 9403's 4 × 24 in (100 × 610 mm) belt at 500 m (1,640 ft)/min; holding the tool firmly with both hands; unplugging before adjustment; centring the belt with the tracking knob while it runs; emptying the dust bag when about half full.
- 2.
Belt Sander 9902 / 9903 / 9920 / 9404, Instruction Manual. Makita.
Used for: The 9903's 3 × 21 in (76 × 533 mm) belt with variable speed of 210–440 m (690–1,440 ft)/min, and the 9902's single speed of 440 m (1,440 ft)/min.
- 3.
50-112 4" x 36" Belt / 6" Disc Sander, Operator's Manual. RIKON Power Tools.
Used for: A 4 × 36 in bench belt with a 6 in disc: 1,900 SFPM belt, 3,450 RPM disc; a gap of no more than 1/16 in between abrasive and tables; the sander fastened to a firm surface; disconnecting before changing accessories.
- 4.
50-122 6" x 48" Belt & 10" Disc Sander with Stand, Operator's Manual. RIKON Power Tools.
Used for: A 6 × 48 in belt at 1,836 FPM no-load and a 10 in disc at 2,510 RPM; work fed into the abrasive on its downward direction.
- 5.
Wood Dust: Possible Solutions. U.S. Department of Labor, Occupational Safety and Health Administration.
Used for: Exhaust ventilation at the source as the preferred control for wood dust, and NIOSH's hazard control sheet for belt sanders.
About this guide
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