Best Joinery for Passageway Door Construction

Cope-and-stick joinery is the classic "man door" method. But what's the strongest joint dowel, mortise and tenon, or what? December 2, 2006

As I work out my business plan, I find myself contemplating *everything*. I know for certain I want to standardize as much as possible, gearing toward the absolute finest methods of construction. I have usually made stave core, cope and stick doors at 1.75 or 2.25 thickness with at least 5/16" skins. However, the more I read about door construction, the more I contemplate steering towards mortise and tenon, or mortise and loose tenon construction, versus cope and stick. I was hoping to gain some input.

Also, what tooling and machinery would you consider necessary for a 1-200 door per month operation that manufactures M&T doors? And what are the differences between the various types of tenoners? What else can a tenoner be used for in a door/stair/custom artisan shop?

Forum Responses
(Architectural Woodworking Forum)
From contributor M:
I'm not going to be presumptuous enough to say that my way of building doors is the best, but it has worked well for me over the years without any problems and has allowed me to build them in a fast, efficient manner. I have a slot morticer that I use to drill dowel holes and then use 3/4"x4" dowels for my construction joints. I use these even on cope and stick doors. I also like to use epoxy as my adhesive of choice, as 90% of the time I'm putting them together myself and I need the extended open time, plus I like the strength of an epoxy joint. One of the advantages of a doweled joint is that your door members are located positively, which allows you to bore or mortice for lock sets before assembly, plus I like the positive registration of my door parts. I too use stave core construction most of the time, but in instances when I've been beaten up on price, I have run solid stiles and rails for interior doors with well dried stock.

From contributor G:
You might note that a cope and stick is a mortise and tenon joint. As long as you use the right one, no additional jointery is necessary. To do this, you may need to have custom cutters made, as we do. Consider the width of the rails. The number of rails in a house door determine the width they need to be.

From contributor D:
I would disagree that a cope and stick joint is a mortise and tenon joint. The cope and stick is an augment to a mortise and tenon, not an equal to or substitute for. Compare glued surface area, since that is what holds the joint together. The tooling for proper cope and stick, mortise and tenon is very involved when one considers all the variables. Hence the nifty shortcut of calling cope and stick a joint. It may work on cabinet doors, but not passage doors. Continue using cope and stick as primary joinery at your own risk. My competitors have helped us quite a bit when their doors fall apart.

From contributor J:
As a matter of strength only, solid tenon into slot mortise is without a doubt strongest. Others come close, and economy of manufacture is always important, but the man asked for the best. A milled cope and stick will help some with strength and keeping faces flush, but M&T is king whether they are used or not.

From contributor G:
If you look at my comment again, I said, "you may need to have custom cutters made, as we do." I think you both know what I am talking about.

From the original questioner:
So how do you integrate a real mortise and tenon joint into a cope and stick door? I'm accustomed to cope and stick, mortise and tenon, mortise and loose tenon... But I've never tried to combine cope and stick and M&T. As for tenons, I'm guessing a double end tenoner is the right machine for the job of tenoning rails. But I've never seen, let alone used, one. How exactly do they work, and what all do they typically do? What would be a decent used "starter" machine and what should I expect to spend? What about the mortise? Hollow chisel? My business plan calls for about 100 doors per month, and about 200 per month by year 3.

I'm trying to get the right machines so that I'm not limping through my jobs, as I have in the past (up to 53 doors per month with no widebelt, no clamp carrier and hand processing).

By the way, with the cope and stick doors I've made in the past, I mortise, countersink, pilot bore and lag the stiles to the rails, then insert an end grain plug which looks like a mortise and through tenon. When I open my new shop (1st week in September) and start producing (1st week in October), that method will be a thing of the past...

Stave core door makers: Do you make or buy your staves?

From contributor O:
If you go for the m&t, then I highly recommend the Maka horizontal oscillating square morticer. The cutters are expensive, but they make the cleanest, fastest mortice I've seen. Even the single headed machines. You see them for $6500 online secondhand. A lot of people say (I'm passing the buck, here) that cope and stick with dowels are all you need, even for big entry doors. I know people who have used dowels for years without problems. For speed, a tenoner and a Maka would be right up there with the dowels, I would think, and I know which have the most gluing area.

From contributor T:
This is a very good question, but not necessarily up to others as to what is best for you to do. The difference here will be determined by sales and marketing. The M&T door tends to be a higher end product, thus setting your pricing and sales into the higher end market. Is this where you want to be? If so, make sure your designs, species and hardware support this same pursuit. Otherwise, the doweled door with cope and stick is a good one and well recognized in the marketplace.

From the original questioner:
I am in the high end market here in Vail, CO. And fortunately, the work finds me here. However, my marketing plan includes internet based sales, also. So I must be competitive in that regard. Contributor M, you said you use a slot mortiser for drilling dowel holes. What exactly is a slot mortiser? Would a horizontal boring machine be appropriate for this task?

From contributor M:
The slot morticer I referred to is a horizontal boring machine. It's a single spindle model that you can use for slot morticing or doweling. It's a Felder FD 250, if you are curious. I have a VFD on it to slow down the RPM's because 3600 RPM's is too fast for a 3/4" drill. It will burn your holes. I do believe that Felder now offers the FD 250 with a VFD on it just for that purpose. In the event you decide to go that route, make sure you get the rack and pinion feed on it rather than just the joy stick, as it gives it much more rigidity.

From contributor C:
From my experience, the cope and stick is run as you already do, and then a mortice is cut in both pieces and a loose tenon of the same material is used. The mortice in the pattern seems a little weird at first, but it ends up perfectly aligned and only needs a little deburring before glue up. We do not do this full time and use a Griggio horizontal mortising machine, which is a cast iron machine with relatively slow rpm and joystick feed and takes a minute or two per slot. There are auto machines out there. The extra square inches of glued joint is essential for long term door slamming and any sunlight exposure. Epoxy is a must. Just look at any old or failed door. Usually it's the cope and stick joint with glue failure and a nice crack opening up.

From contributor N:
It's been a few years, but Fine Woodworking did a comparison article on various joinery techniques. It seems like it was M&T, loose M&T, lag bolted, and of course doweled. They did stress tests and logged the results of failure points. Some of us purists don't want to believe a dowel is stronger than M&T, but this article did.

If you will look at some of the larger company websites (, you will see that they use dowel construction for their assembly method. This particular company makes one of the finest doors I have ever seen, and they warranty them as well. If you are going to stand behind what you make, you would want to have confidence in their strength.

From contributor B:
I don't make many, but I use cope and stick with 3/4 dowels after the door is done. Just drill the edge of door and glue them in. With the stiles and rails, I laminate two pieces of 4/4 or 5/4 to get the thickness. It helps prevent warping.