In the space of a few seconds, a plate joiner (now more commonly known as a biscuit joiner) cuts matching ovoid slots in mating pieces of wood to accept a thin wood biscuit. The glued joint is very strong, and the process is both fast and accurate.

What Counts:
• Ability of machine to cut slots parallel to fence
• Wobble-free plunge mechanism
• Solid fence mechanism

Lamello’s plate joiner, first developed by the small Swiss company in the late 1960s, proved a revelation for cabinetmakers who had been relying on more traditional but time-consuming joinery techniques. A number of other companies have since followed suit with biscuit joiners of their own and there are now at least 10 to choose from.

Biscuits can be used to align parts in a large glue-up, like a table top, and to assemble case pieces, face frames, drawers, and door and window casing. They are not a replacement for traditional joinery everywhere -- they’re not as strong as a conventional tenon for a heavy cabinet door, for instance -- but they have made many jobs easier and faster.

All tools created equal
All biscuit joiners work in essentially the same way. A spring-loaded 4-in.-dia. blade emerges from the tool’s housing and cuts a slot when the joiner is pressed against a solid surface, then retracts when pressure is released. Either an adjustable fence or the base of the tool can be used as a reference surface to make sure slots align with each other.

Biscuits are made from pressed beech and are available in three common sizes (0, 10 and 20) as well as an oversized M. A simple turret-style adjuster, which determines the depth of cut, is set for the size of biscuit that will be used. Some biscuit joiners have other settings and can make slots for hinges and, in one case, small #FF biscuits specifically designed for cabinet face-frames.

Even a small misalignment in matching biscuit slots can spell trouble, so the stability and accuracy of the joiner’s fence system is crucial. There should be no unwanted play in the fence, and it should hold its settings firmly under pressure. For an accurate fit, the slot should be exactly parallel with the fence. Prices range from about $120 to nearly $700.