In this step, I’ll cut the pins and tails and drill holes for the nails. I’m using two finger joints per side, bronze nails and brazing instead of peined dovetails. With a one piece shell and dovetails, the pins are on the shell and become tails when hammered, the joint isn’t auto locking. With two sides, the tails can be on the sides so, when assembled, no (or minimal) hammering is needed to lock things together. I suck at peining (I miss a lot, leave divots and have a hard time judging if the gaps are filled), I don’t like it (so I don’t want to learn), as a result I’m using this joinery. The bronze nails are mainly for visuals (they do do a nice job of holding things together for brazing), otherwise, with steel on steel, the plane body looks like a machined casting (boring although I wish I had to skills to make one). Not better, not worse, just suits me and my skills better.
Cutting the tails
In this case, the tails are 3/4″ and 1 3/4″ long (see the photo under the nails section below). Nothing magical, not critical, I just mark the front and rear of the ramp (on the sole), the start of the heel curve (shell) and about 1/8″ back from the front plate (shell) and remove everything in between, using the gutter as my depth guide.
This photo shows the depth of cut you can take with a roughing end mill, just be really, really careful on the climb cuts; if your mill has backlash, the endmill will grab and jump when you get to the “wall” at the end of the climb pass. I only cut in the other direction, then back out, feed to the other end, start moving and increase the cut, leaving lots of screw up room at the ends. After the bulk is wasted out, I can cut on the center line without worrying about climb cutting (since I won’t be). After roughing, I use a regular endmill to clean up and get square corners.
To mark the pins, I set the shell in the gutter and use a scribe. I also use layout fluid (that ain’t blood. Well, not most of it). For depth, I cut the pins about 1/16″+ proud (in this case a bit over 1/4″).
When clamping in the mill, make sure you use a spacer (in the shell) so that the vise securely clamps the shell. Otherwise, the endmill is unhappy and it is possible to shoot the shell out of the vise (I tested this).
For number of nails and spacing, it is a guess and by eye. Whatever looks good. In this case, 3/16″ (to center) from an edge and 5/8″ for the two center ones. The holes are 3/32″ and total depth is 1/4″ (1/8″ shell + 1/8″ sole).
The vise makes sure the two parts are clamped firmly together, no gaps, when drilling..
Clean up the sole toe and heel; add a chamher and sand/polish.
Now that the body fits together as one piece, I’ll be able to accurately position and install the bridge. Then attach the shell to the sole.