Dado processing
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Methods and equipment for producing dados. October 30, 2003
Question
I prefer to use dado construction for all of my casework for cabinetry. I have been using a cabinet saw with a sliding table attachment to process these dados, but the sliding table is worn out and I need to re-think the dado. I would like to know what you are using to make your dados. I operate a two-man cabinet shop and time is money, so I need to find a way to process these joints for consistency and time. Any advice will help.
Forum Responses
(Cabinetmaking Forum)
Try dovetailing - have a saw blade made with a 7 degree cut and use a router for the female run.
Table saw with power feeder for dadoes close to sheet edge/end. SSC panel router for those in the middle of a top/bottom/tall side.
Turn a radial arm saw into the rip position, add dado blades and slide ends through. Very fast and if you're leaving 1/2" for thickness you don't have to change saw for different thickness boards. Be sure to feed parts against the blade direction. Feeding in with blade direction will redefine land speed records.
You may consider the HerSaf panel router. I've had a used one for about 5 years now, and really am impressed with its speed, quality of cut, versatility, and fast change over for differing widths. I have less than 1600 in mine with new PC router and air clamps.
I use a custom made router table with a 52" uni-fence. The router stays set up for a 1/4" deep cut with a 1/2" wide bit, the uni-fence allows us to quickly make changes in dado placement and once it's locked down it won't move. I had the table built by a local metal worker for very little, put a self edge P-Lam top on it with a plunge router hanging under an aluminum router plate and later added the uni-fence, which I wish I had started with. It's worked great for years.
On the left side of my radial arm saw, I have a 12 ft table with an xacta fence on a 92'' rail. It is for cutting FF stock and boxes, about mid-way of the fence rail I have a 1/4'' 1 1/2 hp, $100 router mounted under table. I put it there just for dado-ing. The fence doubles as a stop on the radial arm saw and on the dado router. The router takes up no space when I drop the spindle. Beats me changing blades or having another table saw. Works like a million bucks and only cost a hundred. The fence started out just as a stop on the radial arm saw but was only about 200. I bought the 92'' long 2''x3'' rectangle tubing and 2x3 angle iron for the rail from the welding shop for $35 and another $10 on paint and bolts.
I am in the process of setting up a Shopbot to do may dadoing. I will be able to do all my drilling and rabbeting in the same setup. You can set up the Shopbot for under $8000 if you build your own table. I have talked to several other small shops using this machine and they all have good things to say.
Just out of curiosity (and I ask this solely from an intellectual standpoint, not to be a pain or suggest you should use another method), what benefits do you feel the dado gives you? Is it principally for strength, alignment of parts in assembly, providing margin for error on joints, combination? I only ask because I used to be all dado myself before switching to staples and screws.
I too switched to the staple and confirmat screw assembly when I made the switch to euro boxes and 3/4" mat. While I was building traditional boxes with 1/2" prefinished ply I felt the dado was quick and strong and allowed for glue adhesion. Now the router table I touted so strongly is collecting dust the same as most of the other equipment I used to use for face frames and the doors that I now outsource. I made the switch to 32mm around the beginning of the year during a slow period and have not looked back. My profit margins are better than ever and we receive more compliments on our work.
When I was doing dados, even though I had a sliding fence attachment, I still used the main saw fence to index all my dados. It only took a couple of minutes to set up (an auxiliary fence) for rabbits, which were all done first, then the auxiliary fence was removed and all grooves and dadoes were done. I also felt like this arrangement gave me more control in keeping "out-of-flat" panels pressed down directly over the dado blade for consistent depth joints. I only used the sliding fence to crosscut parts square.
I use dado construction for my cabinets. I used the Her-Saf panel router with very good success. This is a very accurate machine. I ran this machine for 5 years. The router bit with the removable cutter is the best way to go. This allows you to change for panel thickness at an effective rate. I made the jump to the CNC router so the panel router is gone.
I use a router table, mainly because I can replace the router bit about 15 times for the cost of a new high quality dado set.
Panel router! It works from the face of the panel, has springs that keep the router against the panel face for perfectly even depths even when panels are warped. Easy to stop dadoes - we notch the front of parts that go into the dadoes to get a butt joint look.
Either the Her-saf or Safety Speed Cut are fine, I have used both. I bought the SSC 10 years ago used for $1500 and use it daily. Still perfectly square and accurate. We use the Her-Saf bits mentioned above and wouldn't change that. The only change I made to the panel router is adding a panel to get the working height more comfortable, and bought their dust collection system.
