What the tool does
A plate joiner is a small, flat-bodied power tool with a circular blade about 4 in (100 mm) across, hidden in its base. Pressed against the work and pushed forward, the body slides on its base and the blade plunges out through the face plate, cutting a crescent-shaped slot. A matching slot goes in the other part, a glued biscuit goes into both, and the parts are clamped. Lamello, which developed the system, makes its standard biscuits from beech.
The biscuit's main job is alignment: it holds two edges or faces in register while the glue sets, and a slot is longer than its biscuit, which gives a little sideways adjustment before the glue grabs — Lamello lists an installation tolerance of ± 1.0 mm along the groove for its own. It is used in edge-to-edge panel glue-ups, case corners, T-joints and mitres. Whether a biscuit is the right joint for a given load is decided in choosing a wood joint; no source reviewed here tests how much a biscuit adds, so no strength claim is made.
Biscuit sizes
| Size | Length × width × thickness | Groove depth | Cutter |
|---|---|---|---|
| No. 0 | 47 × 15 × 4 mm | 8 mm | Ø 100 × 4 mm |
| No. 10 | 53 × 19 × 4 mm | 10 mm | Ø 100 × 4 mm |
| No. 20 | 56 × 23 × 4 mm | 12.3 mm | Ø 100 × 4 mm |
| H9 | 38 × 12 × 3 mm | 7 mm | Ø 78 × 3 mm, a separate cutter |
Lamello's figures for its own original beech biscuits, from its catalogue. Other makers' biscuits are their own and may differ in size; check them against the joiner's depth stops before relying on a fit.
The tools reviewed mark their depth stops by these size numbers: DEWALT puts 0, 10 and 20 on its depth knob, and Makita gives one-touch stops for no. 0, 10 and 20. DEWALT's rule of thumb is to use the largest biscuit that physically fits, and it points to no. 20 unless the work is a narrow face frame or picture frame or the stock is 1/2 in or thinner. The small H9 needs its own smaller cutter on a joiner made to take it.
Kinds of plate joiner
| Type | Power | Examples, as each maker lists them | Suits |
|---|---|---|---|
| Corded, fixed blade height | Mains | DEWALT DW682; Makita PJ7000 (701 W, 11,000 rpm); Lamello Classic X (850 W, 10,000 min⁻¹) | General shop work, long sessions |
| Corded, height-adjustable cutter | Mains | Lamello Top 21: cutter raised in 0.1 mm steps up to 4 mm | Centring a slot in the thickness without moving the fence |
| Cordless | Battery | DEWALT DCW682 (20V MAX); Makita XJP03 (18V LXT, 12,000 rpm); Lamello Classic X cordless (18 V, 6,000 min⁻¹) | Work away from an outlet; installation work |
Figures are each maker's for its own tool. Choosing between them is covered in the buying guides. Not a ranking.
Equipment notePaid link
Biscuit joiner
DEWALT DW682K
DEWALT's DW682 from the table above, sold as the DW682K: a corded joiner whose base centres a slot in 3/4 in boards, by its manual.
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Settings that place the slot
| Setting | What it does | Makers' figures |
|---|---|---|
| Depth stops | Match the slot depth to the biscuit size | DEWALT: 0, 10, 20 and M (20 mm maximum, new blade only); Makita PJ7000 and XJP03: six preset stages |
| Fence height | Sets the slot's distance from the reference face | DEWALT: 3/16 to 1-3/8 in from the face to the blade's centreline |
| Fence angle | Cuts slots in mitred and bevelled parts | DEWALT: 0° to 90° plus a reverse 45°; Makita: stops at 0°, 45° and 90° |
| Base registration | References the slot from the tool's base instead of the fence | DEWALT DW682: base 3/8 in from the blade's centreline, which centres a slot in 3/4 in stock |
| Blade | Must match the tool | DEWALT DCW682: 4 in diameter and 1/8 in thick only; Lamello: Ø 100 × 4 mm for no. 0 to 20 |
| Dust | Clears chips from the slot and the air | DEWALT: bag or vacuum adaptor; Makita: vacuum connection; Lamello: 36 mm suction stub |
Settings as each maker gives them for its own tool. A setting from one tool is not a setting for another.
The fence and the base give two ways to reference a cut. Registering from the fence measures from the face the fence rests on, so a slot can be placed anywhere in thick stock; registering from the base measures from the surface the tool sits on, which for DEWALT's DW682 centres a slot in 3/4 in stock without setting the fence. Using either consistently on every mating part is what makes the faces come out flush. Which settings a joiner offers, and which your joints need, is how the plate joiner buying guide compares them.
What a plate joiner is not
- Not a dowel jig. A dowel joint uses round holes drilled to a depth and round pins; see the dowel jig guide.
- Not a loose-tenon machine. Machines such as Festool's Domino cut an elongated mortise for a tenon-shaped insert — a different system with its own tools and inserts.
- Not a substitute for a mortise and tenon. Where a frame joint must resist racking, see mortise and tenon joints.
Working safely
Safety— Unplug before every adjustment
DEWALT's manuals say to turn the tool off and unplug it, or remove the battery, before any adjustment or blade change. Clamp small parts rather than holding them, keep a firm grip on the tool, and let the blade stop before lifting the tool away. See woodworking safety rules.
Layout, cutting and glue-up are taken step by step in how to use a biscuit joiner. The other joinery tools — pocket hole jigs, dowel and dovetail jigs, mortisers — are mapped in the pocket hole guide.
Before cutting biscuit slots
- Biscuit size chosen; the largest that fits the stock
- Depth stop set to that size, checked with a test slot
- Fence height and angle set, or base registration chosen
- The same reference face used on every mating part
- Work clamped; tool unplugged or battery out while adjusting
Sources
Biscuit dimensions and groove depths are Lamello's for its own original wood biscuits; other makers' biscuits are their own and are not assumed to match. Settings, ranges and speeds are each maker's for its own tool, from its manual, catalogue or product sheet. No biscuit is said to strengthen a joint by any amount, and no swelling figure is given, because no source reviewed tests either.
- 1.
Lamello catalogue (English). Lamello AG.
Used for: Original wood biscuits in beech: size 20, 56 × 23 × 4 mm; size 10, 53 × 19 × 4 mm; size 0, 47 × 15 × 4 mm, cut with a Ø 100 × 4 mm cutter; size H9, 38 × 12 × 3 mm, with a Ø 78 × 3 mm cutter; groove depths of 12.3, 10, 8 and 7 mm; an installation tolerance of ± 1.0 mm along the groove. Classic X: 850 W, 10,000 min⁻¹, 20 mm maximum cutting depth, 2.9 kg. Top 21: a cutter that moves up in 0.1 mm steps to 4 mm, 9,000 min⁻¹, 3.5 kg. Classic X cordless: 18 V, 6,000 min⁻¹, 20 mm maximum groove depth, 3.1 kg with battery.
- 2.
DW682 Biscuit Joiner, Instruction Manual (Form No. 632771-00). DEWALT, 2005.
Used for: Depth knob settings 0, 10, 20 and M for the three biscuit sizes, M being the 20 mm (25/32 in) maximum, reached only with a new blade; a fence that places the slot 3/16 in (4.76 mm) to 1-3/8 in (35 mm) from the face, from 0° to 90° and a reverse 45°; a bottom registration surface fixed 3/8 in (9.5 mm) from the blade's centreline, which centres a slot in 3/4 in stock; the largest biscuit that physically fits as a rule of thumb; always turn off and unplug before any adjustment.
- 3.
DCW682 Biscuit Joiner, Instruction Manual. DEWALT.
Used for: A 20V MAX tool with the same 0, 10, 20 and M depth knob and 3/16 to 1-3/8 in fence range; the blade must be 4 in (102 mm) in diameter and 1/8 in thick; turn the tool off and remove the battery before any adjustment.
- 4.
Plate Joiner PJ7000 — product sheet. Makita (Makita Power Tools India).
Used for: A corded plate joiner: 701 W, a 100 mm (4 in) blade, 11,000 rpm, 2.5 kg; cutting depth preset in six stages; a fence lockable from 0° to 90° with positive stops at 0°, 45° and 90°; a dust nozzle that connects to a vacuum.
- 5.
18V LXT® Lithium-Ion Cordless Plate Joiner, Tool Only (XJP03Z). Makita U.S.A..
Used for: An 18V LXT cordless plate joiner: 4 in blade, 3/4 in maximum cutting depth, 12,000 rpm, 6.7 lb with battery; six depth settings with one-touch stops for no. 0, 10 and 20; a pivot fence with positive stops at 0°, 45° and 90°.
About this guide
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