I have decided against building a practice door.
Instead, I’m looking at the construction process of a sequence of sub-projects that build door parts. I figure I can practice each step before I do it, and throw out any parts that don’t work out.
The first sub-project in the door building process (described here) seems to be to build the cores for the stiles and rails. canadianchips suggested red cedar for the core because it is relatively light weight. It also is relatively cheap and easy for me to get, so I got a stack of 10 ft 2×6s:
Big Sticks to Little Sticks
The first step of this process is to cut the big sticks into little sticks. I thought I read somewhere to avoid running stock shorter than 18” through my planer – maybe it was the manual, maybe it was an hallucination. So I chopped the big sticks into 30” sections with the miter saw, and then ripped each section into 3 sticks on the bandsaw, producing this stack of parts.
After jointing and planing these pieces came out to 1-3/4” x 1-1/2”. I then cut them in half to 15” length, and where necessary cut out cracks and troublesome-looking knots. I decided to glue them up into cores that were 1-1/2” thick which I would subsequently joint/plane down to 1-1/4” before applying the 1/4” skins. Unfortunately, although my finger joint bit has a cutting length of 1-1/2”, it will only finger-joint to a thickness of about 1-1/4”. I figured out that if I finger joint the center 1-1/4” of the thickness I would end up two “fat fingers” on the top and bottom; if I then removed the fat finger on the top of one piece and the bottom of the mating piece they would fit together properly.
Here is a batch of parts with the finger joints milled. On the early batches I discovered that the bit was pulling the work into the bit a little, so when I was milling the later batches I clamped the work to the miter gauge.
Little sticks to big sticks
I have 3 8’ lengths of 2” square steel tube, and 3 6’ lengths of 2” angle iron that I use for supporting temporary assembly tables. I used the tubes to support a scrap of plywood, and leveled/shimmed/clamped to make a flat gluing table. I used two of the angle irons to form a straight fence. I drilled holes in the center of each part so I could screw it down to the table as I glued up the butcher-block assembly. I used 2-1/2” Kreg screws and added a “washer” of 1/4” hardboard. I drive these screws with a drill, but then do the final torquing by hand to ensure that they are tight and minimize the frequency that I strip them out.
It was not so easy getting the finger joints to mate up tightly. I used a 50” bar clamp to pull each finger joint together before screwing down the piece. End-to-end butt joints would have made the glue up much easier, and it seems to me it wouldn’t weaken the assembly if these joints were staggered. Given that this will be an interior door I suspect this construction method is overkill for the application, so I’m not going to worry about the relatively loose finger joints. If I ever do them again I will probably make some sort of clamping fixture to get and keep the finger joints tight. I might even do one strip at a time first, joint the sides of the strips, and then glue the strips side-by-side in a second glue step.
Here is a shot of the rough cores. The rail cores all have 1/2” holes in them lengthwise for 3/8” allthread that will pull the outside stiles together horizontally in the final door assembly.
lilredweldingrod suggested using loose tenons for the final assembly, and I plan on doing this. He also suggested making all the stiles full length. I’m opting to make only the outside stiles full length and keeping all the rails from outside stile to outside stile. I’m thinking that with the allthread running the full width of the door I’ll be able to pull the door together into the final assembly while dry fitting and later when gluing, and this will help me figure out how to get the whole thing square in the end.
-- Greg D. -- the price of freedom is tolerance