You can inlet both sides, only one side, or use a three-piece construction adding a frame around the tang of a third piece that is just a tad thicker than the tang (frame handle). All work very well. If using good epoxy and a good fit, mechanical fasteners are not absolutely required, but common practice is to use one, two, or three pins/rivets/bolts. In some cases, the cause more trouble than they are worth.
Tang holes should be about twice the diameter of the pins/rivets/bolts used. This allows for pushing the handle tight against the guard/bolster and for a little misalignment in drilling. Drilling the tang the same as the rivets is going to cause curse words later on.
1) To get ready for the handle, HT and finish all sanding and shaping on the blade. Remember to drill the tang holes before HT. Even if not using pins, holes in the tang are a good practice.
2) Tape the blade up with blue painter's tape to keep it clean of epoxy and cover the semi-sharp edge.
3) Cut the handle block in half as cleanly as possible. A table saw works well. If using pre-cut scales this is already done.
4) Sand the mating surfaces FLAT. Use a granite surface plate or a sheet of 1/4" glass with a piece of 120 grit sandpaper taped on it to sand the mating surfaces. Sand in a slow figure-8 pattern. No need for finer sanding than 120 grit. It provides the perfect gluing surface.
If doing a frame handle skip to step 7).
5) Mark the tang position on the inside of both pieces (or only one side) and mortice out the channels. You can do it on both sides or just one side. Test the fit by clamping the scales together and inserting the tang in the channel. You want a smooth slide in-out ... not too tight not too loose.
Once the channel is done, clamp the two halves together and finish the end where it will meet the guard or bolster. (If no guard or bolster, just sand them even).
6) Hopefully, you already drilled the tang with a hole (or holes). If not, drill the tang with a hole using a carbide drill bit. Again, you want the holes in the tang about twice the diameter of the pin/rivet size you will use. On two-piece handles on kitchen knives, I install two or three Corby bolts.
7) Fit the blade with any guard or bolster that you will use and then place one scale on the tang. If these will be soldered, do that before assembly of the handle. Push one scale down snug against the guard/bolster and clamp in place. Mark the holes in the tang on the wood. Remove the scale and drill the center of each tang hole mark for the rivets/pins. Use a drill bit smaller than the pin/rivet/bolt size. I use a 1/8" bit that matches the 1/8" hardwood dowels I use in the next steps.
Remove the knife blade and clamp the scales together and drill through the second side on the first hole only. Rubber bands work well here as clamps. You can also tape the scales together with electrical tape. Tap a hardwood dowel through the holes (taper one end to make it go through easier). If there is more than one pin hole, drill the others, inserting a dowel as you drill them.
Once the handle is assembled with the dowels, cur them off flush with the scales. A tiny dot of glue on each side will keep them tight. SHahe the hand;e as desired and sand to 400 grit. Sand the end where it will meet the guard/bolster flat. If there will be no guard/bolster, sand end to the desired shape. Sand or buff to the desired finish. Tap out the first dowel and redrill to fit the pin/rivet/bolt. Temporarily install that pin and drill the others, installing the pins as you go.
8) Test fit everything one last time before final glue up. If all is good, glue the handle up with slow cure epoxy. 24-hour epoxy is best.
If using Corby bolts, the bolts are the clamps. If using pins use light weight clamps. Don't use C-clamps or super strong spring clamps. All you want to do is hold things in place snug while the epoxy curses. A gluing jig that pushes the handle into the blade/guard is a good thing to build. It also makes handling and cleaning the blade during glue up easier.
9) Wipe off any drips and such with a paper towel followed by a paper towel dampened with denatured alcohol. Alcohol is the correct solvent for uncured epoxy. Cured epoxy can be removed with acetone.
10) Set the knife aside, butt down, and monitor the glue pot to see when the epoxy starts to gel. When the epoxy in the mixing pot starts to gel, check the knife for any squeeze-out and wipe off with a paper towel and alcohol. Set aside to cure overnight.
11) Once cured, drill the handle through the holes on the one side using the same size bit as before. Then re-drill the holes for the pins/rivets/bolts/.
12) Finish the handle, un-tape the blade, and sharpen your knife. Make sure to do all sanding and buffing before you un-tape the blade.
