The first thing the Domino has going for it is the size and shape of the fasteners. There are several sizes available, and I picked one about the size of the tenon I would make if I were making traditional mortise-and-tenon joints. The next advantage is the optional attachment for centering the machine in the width of narrow stock. This makes a scary operation with the biscuit joiner safe and secure. It also eliminates the need to mark the center of the workpiece for alignment.
There is also a clear area on the fence marked with a graduated grid. When it came time to make the slots at the mitered cutouts, I used the grid to center the machine. Because of these notches, these slots needed to be deeper than the slots on the ends of the adjacent parts. This adjustment, like all adjustments on the Domino, is quick and easy once you’re familiar with the machine. There is also an adjustment for the width of the slot. It can be set to the precise width of the insert, or a little wider to provide for some lateral adjustment. I cut the slots in the ends of the narrow rails to the width of the loose tenons, and cut the mating pieces wide to let me fit the joints exactly where I wanted them.
The Domino is a bit bigger and heavier than a biscuit joiner, but it is nicely balanced so it is comfortable to handle and use. The dust -ollection port attached to a shop vacuum worked well, and setting up the fence and depth of cut, and installing the bit, were all straighforward and simple operations. Because of the beads in my stock, I set the loose tenons below center in the thickness of the stock.
There is a slight learning curve with the Domino. For the loose tenons to fit, the tool must be held correctly. If the fence isn’t flat on the face of the piece being cut, the mortise slot will be at an angle and the parts won’t line up. It is also critical to plunge the cutter into the work in a smooth motion. Any deviation from straight in or straight out will result in a sloppy mortise. It took me a while to get the hang of it , practicing on some scraps before diving into a project would have been a good idea.
I had a few joints I needed to recut. I glued a tenon in the mis-cut mortises, waited for the glue to dry, trimmed the tenon flush and recut the joints. When I assembled the frame I glued and clamped in two stages, working from the center out. The first clamping was the three intermediate stiles (and the narrow rails between them) in between the upper and lower rails. There are a lot of pieces, and it’s important to keep all the openings square. The two-step glue-up makes assembly of the frame less hurried and less stressful.
One of the ways I keep the joints square is to clamp square blocks in the corners. Putting these in place as the assembly is glued prevents the clamps from racking the joints out of square. You can buy these, or you can cut them from scrap plywood. I recommend that you cut them from scrap plywood, and spend the money you save on a T-shirt or mug from the Popular Woodworking store.
I was impressed with the Festool Domino. Like most of this company’s products, it isn’t just a tool, it is a system of working. Festools’ engineers and designers did a wonderful job of developing a way to make strong joints quickly. The one reservation I have is the price, but if I were in a situation where I needed to make loose tenon joints on a regular basis, I would buy a Domino in a heartbeat. As a part-time, amateur woodworker it would be harder for me to justify the expense.