Dominos

Dominos are the loose-tenon stock used with the Festool Domino joiner — small, rounded-edge tenons, most commonly beech, sized to match the joiner's cutter widths and installed glued into matched mortises on both mating pieces. If the Domino tool cuts the joint's sockets, these are the actual pieces that become the joint once glue goes in and the assembly is clamped up.

Sizing

Dominos are sold in a matrix of widths (matching the cutter/mortise width used) and lengths, sized to the two Domino tool models — the DF 500 covers a smaller range suited to furniture-scale joinery, the DF 700 XL a larger range for bigger stock. Picking the right combination of width and length for the joint's structural demands (thicker material, more length in the mortise) is a real design decision, not just a default setting to leave alone.

Material

Beech is the standard and default — dense, stable, and a reliable glue-bond partner for most domestic and imported species used in furniture work. Other species (including some exotic and marine-grade options for outdoor or high-moisture applications) exist for specific needs, but beech covers the overwhelming majority of use cases.

Why loose tenons instead of an integral one

A traditional mortise-and-tenon joint cuts the tenon as part of one workpiece, matched to a mortise in the other — which means the tenon's grain direction and the joint's geometry are fixed by which piece you decided to cut the tenon into. A loose tenon (whether a Domino or a shop-made equivalent) decouples that decision: both pieces get identical mortises, and a separate tenon — cross-grain relative to neither piece specifically — joins them. That flexibility is part of why loose-tenon joinery has become so common in modern furniture-making.

Buying notes

Because Dominos are a specific, proprietary size standard tied to the tool, they're not a commodity item the way dowels are — budget for them as an ongoing project material cost, similar to how you'd budget for hardware, rather than a one-time shop purchase.