Greetings, everyone
I purchased a Domino recently, based in part on the presentations I have seen here, in part on a demo at my local Festool dealer, and in no small part on the experience I have had with other Festool products. Many of the other reviews are long, elaborate--and very impressive--presentations by long-time owners and experienced users. I thought I would add my experiences as an eager--but motivated--novice. I should add that I also own a Mafell (used to be called Hoffman in the US) doweling machine, which looks and works very much like the Domino. The big difference is it drills two adjacent dowel holes at one time, rather than a single slot mortise. So I had no problem anticipating and adapting to the Domino system workflow. And now, my novice's review.
The Domino is basically a plunge router that employs a rotating, oscillating bit to cut a slot--i.e. mortise--in a workpiece. The concept is simple: A mortise is formed in two workpieces to be joined, a wooden tenon of appropriate dimension (the "domino") is glued into both mortises, and the workpieces are clamped up. The Domino accommodates several sizes of bit, and Festool sells the matching dominos. In use, the Domino registers against the workpiece. If either the workpiece or the Domino offer inadequate bearing surface, the registration is unstable. Festool offers accessory pieces which are attached to the machine to improve stability, when necessary. Another accessory is provided to allow the Domino to register off a previously-cut mortise, in which case the machine can cut a line of equally-spaced mortises.
The overall build quality of the Domino is high--like most Festool products. The machine has plenty of power, feels solid, and runs smoothly. Dust collection is excellent. The joinery system is intuitive, and appropriate workflows are easy and convenient to devise. The Domino dramatically reduces the time and effort needed to implement M&T joints. For example, a frame (as, say, for a cabinet door) can be joined with four tenons, one in each corner. This process, from start to finish, takes about five minutes, and is much less complicated and fussy than other methods. No router tables, cope-and-stick cutters, coping sleds, etc. In fairness, the Domino does not address the inner-edge profiling, which is incorporated into the cope-and-stick method, but such profiles--if needed at all--can easily be handled by other means. The resulting M&T joints make for a stronger frame than the tongue-and-groove joints associated with the cope-and-stick method.
The size of the project to be joined is limited by the size of the joints, which in turn is limited by the available cutter sizes and tenon sizes. The Domino handles small-to-medium size projects very well. Cabinet doors? Yes. Passageway doors? Maybe. Entry doors? No way. End tables, coffee tables, night stands? Yes. Dining tables? No. Chairs? Maybe. By the way, Festool will soon release the Domino XL--a significantly larger machine--to handle larger projects.
The Domino has two problems. One is flexibility. The cutter diameters are fixed, providing for slots of 4, 5, 6, 8,and 10mm widths. Not a serious limitation, but there is no convenient way to cut, say, a 15mm slot with the 8mm bit by making two parallel, overlapping slots. Such a capability is routine on a horizontal slot mortiser, a vertical square-bit mortiser, or an M&T jig like the Leigh FMT. In any case, such a slot would not match the thickness of the supplied tenons, which would then have to be specially made. Another limitation is the distance by which the cutter can be offset from the workpiece edge. Several "standard" (metric) workpiece thickness can be preset, but it's awkward to implement an offset distance other than the standard ones. A third limitation is plunge depth. This is also controlled by presets, which are adequate in most cases. All in all, thee limitations do not seriously compromise the usefulness of the Domino, but it is interesting to note that they have been addressed in the design of the new Domino XL.
The second--and more serious--problem is accuracy. The Domino is capable of sufficient accuracy, but only if properly adjusted. Unfortunately, the adjustments are difficult and awkward to make, and only partially effective.
The primary method for positioning the Domino is to set the workpieces as they should be mated, scribe a line squarely across both pieces, then separate the pieces and cut the mortises. This should result in mortises that are centered on the lines. The Domino has a plastic sight gage for aligning the machine with the scribed line. If this gage is not centered properly, the mortises will be off center, and the centering misalignment will be doubled when the pieces are assembled. The gage can be loosened, slid slightly to one side or another, and retightened, to correct this alignment error. This involves tedious trial-and error, because there is no method for moving the gage precisely and systematically. A small feed-screw mechanism would be helpful, especially if the screw had 1mm threads. It's easy to measure the misalignment on the test mortises (a metric caliper helps), and it would be easy to adjust such a feed screw by 1/4mm just by looking at the screw head. No need for micrometer markings. Note that a 1/4mm centering error translates into a 1/2mm joint-misalignment (between 1/32" and 1/64"), which I would consider the maximum allowable error. On my machine, I achieved this spec after an hour of trial-and-error cuts, with the aid of a feeler gage to estimate how much I was sliding the sight gage. When I assemble the joint, I take a thin shaving off both sides of the tenon with a block plane. This gives me just a bit of side-to-side play. Note that the Domino also provides the ability to cut the mortises oversized, but only by two preset, significant amounts. This capability is used when the side-to-side alignment is not critical, such as when building up a tabletop by edge-jointing multiple boards, the ends of which will be trimmed anyway.
There is another way to register the Domino. A pair of retractable indexing tabs is provided--one on each side of the cutter--which when engaged, position the cutter at a fixed distance from the tab. This is a quick way to make frame joints (assuming the frame parts are an appropriate width)--no need to measure at all. Any discrepancy between the left and right tab-to-cutter distances will result in a misaligned joint, again by twice the error. On my machine the initial error was 0.70mm, resulting in a 1.4mm error in the joint. The end of the stile would not be flush with the outer edge of the rail--off by 1.4mm--which is not acceptable. Festool provides replacement tabs that are slightly undersize. The manual advises the user to replace one of the two tabs to reduce the cutting error. On my machine, this reduced the tab spacing discrepancy to 0.3mm, for a joint error of 0.6mm. Outer frame edges are often profiled, in which case the joints must be dead flush, so a discrepancy must be removed with a block plane, edge sander, or some other means. Again, I shave the tenon lightly to provide just a bit of side-to-side play, although it's difficult to force the joints into alignment at glue-up, because the panel is in place. Another difficulty with this indexing system is that there is some side-to-side play in the tabs, due to the way they are mounted. A better system would use tabs with no play, but with screws inserted in the tabs such that the screw heads contacted the workpiece. The screws could then be used to modify the tab-to-cutter distance for each side. A big improvement, at a modest cost.
In summary, the Domino is a robust machine that does its job reliably and well, and most importantly, quickly. Its limitations and problems are not serious, and once understood, are easily addressed. If the Domino is to be used on a project, it helps to keep in mind the machine's "preferences" for certain part sizes when designing. For example, if an apron is to be tenoned to a tale leg, plan the apron set-back such that tenon will be placed roughly in the center of the apron, using the fixed depth presets. In other words, understand what the tool wants to do, and work with it.
I purchased a Domino recently, based in part on the presentations I have seen here, in part on a demo at my local Festool dealer, and in no small part on the experience I have had with other Festool products. Many of the other reviews are long, elaborate--and very impressive--presentations by long-time owners and experienced users. I thought I would add my experiences as an eager--but motivated--novice. I should add that I also own a Mafell (used to be called Hoffman in the US) doweling machine, which looks and works very much like the Domino. The big difference is it drills two adjacent dowel holes at one time, rather than a single slot mortise. So I had no problem anticipating and adapting to the Domino system workflow. And now, my novice's review.
The Domino is basically a plunge router that employs a rotating, oscillating bit to cut a slot--i.e. mortise--in a workpiece. The concept is simple: A mortise is formed in two workpieces to be joined, a wooden tenon of appropriate dimension (the "domino") is glued into both mortises, and the workpieces are clamped up. The Domino accommodates several sizes of bit, and Festool sells the matching dominos. In use, the Domino registers against the workpiece. If either the workpiece or the Domino offer inadequate bearing surface, the registration is unstable. Festool offers accessory pieces which are attached to the machine to improve stability, when necessary. Another accessory is provided to allow the Domino to register off a previously-cut mortise, in which case the machine can cut a line of equally-spaced mortises.
The overall build quality of the Domino is high--like most Festool products. The machine has plenty of power, feels solid, and runs smoothly. Dust collection is excellent. The joinery system is intuitive, and appropriate workflows are easy and convenient to devise. The Domino dramatically reduces the time and effort needed to implement M&T joints. For example, a frame (as, say, for a cabinet door) can be joined with four tenons, one in each corner. This process, from start to finish, takes about five minutes, and is much less complicated and fussy than other methods. No router tables, cope-and-stick cutters, coping sleds, etc. In fairness, the Domino does not address the inner-edge profiling, which is incorporated into the cope-and-stick method, but such profiles--if needed at all--can easily be handled by other means. The resulting M&T joints make for a stronger frame than the tongue-and-groove joints associated with the cope-and-stick method.
The size of the project to be joined is limited by the size of the joints, which in turn is limited by the available cutter sizes and tenon sizes. The Domino handles small-to-medium size projects very well. Cabinet doors? Yes. Passageway doors? Maybe. Entry doors? No way. End tables, coffee tables, night stands? Yes. Dining tables? No. Chairs? Maybe. By the way, Festool will soon release the Domino XL--a significantly larger machine--to handle larger projects.
The Domino has two problems. One is flexibility. The cutter diameters are fixed, providing for slots of 4, 5, 6, 8,and 10mm widths. Not a serious limitation, but there is no convenient way to cut, say, a 15mm slot with the 8mm bit by making two parallel, overlapping slots. Such a capability is routine on a horizontal slot mortiser, a vertical square-bit mortiser, or an M&T jig like the Leigh FMT. In any case, such a slot would not match the thickness of the supplied tenons, which would then have to be specially made. Another limitation is the distance by which the cutter can be offset from the workpiece edge. Several "standard" (metric) workpiece thickness can be preset, but it's awkward to implement an offset distance other than the standard ones. A third limitation is plunge depth. This is also controlled by presets, which are adequate in most cases. All in all, thee limitations do not seriously compromise the usefulness of the Domino, but it is interesting to note that they have been addressed in the design of the new Domino XL.
The second--and more serious--problem is accuracy. The Domino is capable of sufficient accuracy, but only if properly adjusted. Unfortunately, the adjustments are difficult and awkward to make, and only partially effective.
The primary method for positioning the Domino is to set the workpieces as they should be mated, scribe a line squarely across both pieces, then separate the pieces and cut the mortises. This should result in mortises that are centered on the lines. The Domino has a plastic sight gage for aligning the machine with the scribed line. If this gage is not centered properly, the mortises will be off center, and the centering misalignment will be doubled when the pieces are assembled. The gage can be loosened, slid slightly to one side or another, and retightened, to correct this alignment error. This involves tedious trial-and error, because there is no method for moving the gage precisely and systematically. A small feed-screw mechanism would be helpful, especially if the screw had 1mm threads. It's easy to measure the misalignment on the test mortises (a metric caliper helps), and it would be easy to adjust such a feed screw by 1/4mm just by looking at the screw head. No need for micrometer markings. Note that a 1/4mm centering error translates into a 1/2mm joint-misalignment (between 1/32" and 1/64"), which I would consider the maximum allowable error. On my machine, I achieved this spec after an hour of trial-and-error cuts, with the aid of a feeler gage to estimate how much I was sliding the sight gage. When I assemble the joint, I take a thin shaving off both sides of the tenon with a block plane. This gives me just a bit of side-to-side play. Note that the Domino also provides the ability to cut the mortises oversized, but only by two preset, significant amounts. This capability is used when the side-to-side alignment is not critical, such as when building up a tabletop by edge-jointing multiple boards, the ends of which will be trimmed anyway.
There is another way to register the Domino. A pair of retractable indexing tabs is provided--one on each side of the cutter--which when engaged, position the cutter at a fixed distance from the tab. This is a quick way to make frame joints (assuming the frame parts are an appropriate width)--no need to measure at all. Any discrepancy between the left and right tab-to-cutter distances will result in a misaligned joint, again by twice the error. On my machine the initial error was 0.70mm, resulting in a 1.4mm error in the joint. The end of the stile would not be flush with the outer edge of the rail--off by 1.4mm--which is not acceptable. Festool provides replacement tabs that are slightly undersize. The manual advises the user to replace one of the two tabs to reduce the cutting error. On my machine, this reduced the tab spacing discrepancy to 0.3mm, for a joint error of 0.6mm. Outer frame edges are often profiled, in which case the joints must be dead flush, so a discrepancy must be removed with a block plane, edge sander, or some other means. Again, I shave the tenon lightly to provide just a bit of side-to-side play, although it's difficult to force the joints into alignment at glue-up, because the panel is in place. Another difficulty with this indexing system is that there is some side-to-side play in the tabs, due to the way they are mounted. A better system would use tabs with no play, but with screws inserted in the tabs such that the screw heads contacted the workpiece. The screws could then be used to modify the tab-to-cutter distance for each side. A big improvement, at a modest cost.
In summary, the Domino is a robust machine that does its job reliably and well, and most importantly, quickly. Its limitations and problems are not serious, and once understood, are easily addressed. If the Domino is to be used on a project, it helps to keep in mind the machine's "preferences" for certain part sizes when designing. For example, if an apron is to be tenoned to a tale leg, plan the apron set-back such that tenon will be placed roughly in the center of the apron, using the fixed depth presets. In other words, understand what the tool wants to do, and work with it.
