Festool's Domino isn't just a brand new type of joining tool; it's a whole new joining system. Based on mortise-and-tenon joinery, the Domino combines the qualities of biscuits and dowels with a stronger, self-aligning joint. A loose tenon of solid beech called a Domino fits into a slot cut by the tool, saving the time and labor of cutting out exacting tenons, especially on tricky mitered or beveled joints. Five sizes of Domino tenons are available from 3/16 by 1-1/8 inch to 3/8 by 11-5/16 inch, and the smallest can be used on the end of a piece of stock as small as 5/8 by 7/8 inch.
The action of the tool is similar to that of a biscuit joiner: The spring-loaded head that conceals the cutter is lined up against the edge of the stock, and then the cutter is plunged into the wood.
But instead of leaving a semicircular kerf, the router-type cutter of the Domino oscillates side to side and creates a wide, flat groove with curved sides. Mortising with different diameter bits allows for Domino tenons of different thicknesses, and preset depth settings on the machine allow for the different lengths. Besides the exact width of the tenon, there are two increased cutting-width settings that can make up for slight mortise position inaccuracies when lining up the joint.
To set up the tool for a mortise, the front fence is set for height and angle and the cutting is usually done with the fence riding atop the workpiece. The center of the joint is approximated; the range of height adjustment can align the cutter to the center of stock from 9/16 up to 2-1/2 inches thick and there are preset height stops and a graduated scale, both in millimeters. The fence has a 90-degree setting range and features positive stops at common adjustment angles.
All of the articulations and adjustments have a really solid feel and speak to the apparent tight tolerances and overall superb quality of the machine, something Festool is known for throughout its entire product range.
When making simple mortises, perpendicular to the joint edge, I found that when working on a reliably flat surface I could just hold the stock being joined and the bottom of the Domino flat on the table instead of guiding with the fence. I set the fence height just above the workpiece thickness so I could still use the front handle for stability and line up my cuts with the arrow on the center of the unit. Using the bottom side as a reference like this gave me more control, especially with smaller pieces, and the base's fixed 3/8-inch (1-cm) cutter height was just right for using this method with 3/4-inch stock. In any case though, you have to make all of the cuts for an assembly from the same reference side; trying to find the exact center of a board and then cutting from either side can lead to a series of small errors that add up to overall inaccuracy.
While the placement of Domino tenons can be fairly random, the only concern is that they line up with their mating mortise. To make this easier, retractable guide pins are spaced 1-7/16 inches from the center of the cutter. These are used to make an accurate, repeatable mortise a fixed distance from the edge of your board and can be linked from hole to hole along an edge but result in mortises just a few inches apart. For a wider and more desirable spacing pattern, an adjustable stop accessory is available that can space mortises up to 8 inches apart. For those times when an exact mortise position is necessary, such as on the end of a delicate chair stretcher, a centering attachment also is sold that will handle material as thin as 7/8 inch.
Besides one bit, the only included accessory is a support stand that is attached to the base to add stability when making mortises on the face of a wide yet thin board with the motor positioned vertically, like a router. When used with a vac, the Domino's very efficient dust collection system keeps it from being clogged with chips and the quick-disconnect cord is very handy when changing bits or storing the unit in its high-tech Systainer-system case. Domino tenons and different size bits must be purchased separately; the tenons are available in a high-quantity assortment Systainer case.
For novice and seasoned wood joiners alike, the Festool Domino provides an easy and accurate system for strong joints in countless configurations. Using the index pins really speeds up mortise layout and reduces much of the manual marking and its potential for accumulated errors that other methods require. Sure, it's expensive, but better and faster results are always worth investing in.
–Michael Springer is senior editor for Tools of the Trade.