Choose the motion, not the motor
Every sander drives abrasive across wood; what differs is how. The motion decides how fast it removes wood, what pattern of scratches it leaves, whether it can reach a corner or follow a curve, and whether it keeps a surface flat. Grits, sequences and where to stop are the same whichever machine you use — they are in how to sand wood, sandpaper and the grit chart.
| Machine | Motion | Suits | Limits |
|---|---|---|---|
| Random orbital (handheld) | A round pad orbits and spins freely | General sanding of flat and gently curved surfaces | A round pad cannot reach into inside corners |
| Sheet or palm (handheld) | A rectangular pad moves in a small fixed orbit | Flat surfaces up to an edge; uses cut paper sheets | Fixed orbit; pad sizes are small |
| Detail (handheld) | A triangular (delta) pad, orbital | Corners and awkward angles | Small pad; slow on large areas |
| Belt (handheld) | A belt loop runs in a straight line under a flat platen | Fast stock removal and levelling on large flat work | Aggressive; not a finishing machine |
| Belt, disc or combination (bench) | A fixed belt or a spinning disc; work is brought to it | Shaping, squaring and smoothing small parts and ends | Work must fit the tables; a stationary machine |
| Drum (stationary) | A rotating drum over a powered conveyor | Bringing boards and panels to even thickness and flat | Not a planer; sized by drum length and passes |
| Spindle (bench) | A spindle spins and moves up and down | Inside curves and edges of shaped parts | The sleeve diameter sets the tightest curve |
Motions as the makers' manuals and pages describe their machines; each guide below has the figures for named models.
Handheld sanders
- Random orbital. A general-purpose handheld sander. Its pad's centre travels a small circle while the pad spins freely, so the scratch path keeps changing. Bosch describes the orbit of its ROS20VSC two ways — a 3/32 in orbit diameter and a 3/64 in eccentric offset — which is why orbit figures need their maker's definition. See random orbital sanders and how to use one.
- Sheet (palm, finishing) and detail. A fixed orbit on a flat pad: Makita's BO4556 runs a 4-3/8 × 4 in pad at 14,000 orbits per minute, and takes cut sheets of paper. Detail sanders put a triangular pad into corners. See detail and palm sanders.
- Belt. A belt loop driven over two drums, pressed flat by a platen; Makita's 9403 runs a 4 × 24 in belt at 1,640 ft/min, and Makita says to hold it with both hands. It is used to remove stock and level surfaces rather than to finish them, and a tipped platen digs in. See belt sanders.
Stationary and bench sanders
- Bench belt, disc and combination sanders bring the abrasive to the work: RIKON's 50-122 pairs a 6 × 48 in belt with a 10 in disc, and its manual says to feed work into the abrasive on its downward side. See benchtop sanders.
- Drum sanders carry boards on a conveyor under a rotating drum. SuperMax's 19-38 has a 19 in drum and sands 38 in wide in two passes; its manual says to feed against the drum's rotation. See drum sanders.
- Spindle sanders spin a sleeved spindle that also oscillates: JET's JBOS-5 runs at 1,725 rpm with 30 oscillations a minute, on sleeves from 1/4 to 2 in. See spindle sanders.
Dust: a health and a fire question
OSHA lists respiratory illness and cancer among the effects of wood dust, and names exhaust ventilation at the point where dust is made as the preferred control; respirators, it adds, need a respiratory protection program behind them. A sander's own dust port, its onboard bag or box, and an external extractor are three different things — NIOSH measured a large reduction in emissions only for a specific exhaust system it designed and tested. The collected dust is also a fire risk: Milwaukee warns that dust from sanding coatings such as polyurethane or linseed oil can self-ignite in the dust box, and says to empty it often.
Choosing one
For a first sander, the job decides: choosing a sander routes from the job to the type, and each type has its own buying guide — random orbital, cordless random orbital, mini random orbital, cordless palm and detail, belt, benchtop, benchtop drum and portable. Abrasive buying is in choosing sandpaper.
Choosing the machine type
- The surface: flat, curved, inside a corner or an end
- Removal or finish: levelling stock, or smoothing it
- Handheld to the work, or the work to a bench machine
- The abrasive format the machine takes
- Dust: the port, the bag and an extractor
- The machine's manual read before first use
Sources
Machine figures are each maker's for the model named, in the maker's own terms; they illustrate each type and are not a comparison between types. Abrasives and sanding technique are covered on the finishing pages and linked rather than repeated.
- 1.
ROS20VSC 5 In. Random Orbit Sander/Polisher. Bosch.
Used for: A random orbit sander's orbit diameter (3/32 in) and eccentric offset (3/64 in), and its 5 in hook-and-loop pad.
- 2.
Finishing Sander BO4555 / BO4556, Instruction Manual. Makita.
Used for: A finishing (quarter-sheet) sander with a 4-3/8 × 4 in pad at 14,000 orbits per minute.
- 3.
MOUSE Detail Sander, 1.2 Amp, Corded (BDEMS600). BLACK+DECKER.
Used for: A detail sander whose pad fits odd and awkward angles, with a detail finger attachment for hard-to-reach spots.
- 4.
Belt Sander 9403 / 9921, Instruction Manual. Makita.
Used for: A 4 × 24 in handheld belt sander at 1,640 ft/min, held with both hands.
- 5.
50-122 6" x 48" Belt & 10" Disc Sander with Stand, Operator's Manual. RIKON Power Tools.
Used for: A bench combination sander with a 6 × 48 in belt and a 10 in disc, its work fed on the abrasive's downward side.
- 6.
19-38 Drum Sander, Owner's Manual. SuperMax Tools (Laguna Tools).
Used for: A drum sander feeding boards on a conveyor against the drum's rotation, 38 in wide in two passes on a 19 in drum.
- 7.
JBOS-5 Benchtop Oscillating Spindle Sander, Owner's Manual. JET.
Used for: An oscillating spindle sander: spindle at 1,725 rpm, 30 oscillations a minute, sleeves from 1/4 to 2 in.
- 8.
M18 Random Orbit Sander 2648-20, Operator's Manual. Milwaukee Tool.
Used for: Sanding dust from coatings such as polyurethane or linseed oil able to self-ignite in a sander's dust box.
- 9.
Wood Dust: Hazard Recognition. U.S. Department of Labor, Occupational Safety and Health Administration.
Used for: Wood dust's health effects, including respiratory illness and cancer.
- 10.
Wood Dust: Possible Solutions. U.S. Department of Labor, Occupational Safety and Health Administration.
Used for: Exhaust ventilation at the point where dust is produced as the preferred control, and respirators requiring a respiratory protection program.
- 11.
Control of Dust Exposure for Random Orbital Hand Sanders (Engineering Controls Database). National Institute for Occupational Safety and Health.
Used for: A tested random orbital sander exhaust system and the wood-dust health effects NIOSH lists.
About this guide
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