Similar to the Hidden Tang Pinned tutorial and the Through Tang tutorial, this method requires the tang be tapered in both dimensions.
This build is a little unorthodox. Most makers will slot a hardwood dowel and build the handle from two or more pieces with the ferrule end slotted before glue up. That method is okay, but because the slot is made before shaping the handle, the facets of the octagon must be perfectly true to the slot. In this method, I make the best octagon I can, then slot it for accepting the tang.
For color, I've got some 1/4" thick Inlace Acrylester which is Abalone, which is a blend of kind of greens, blues, violets and reds. Really cool stuff that the pen turners love.
With a target handle length of 4.25" (108 mm) I start with a block of Cocobolo that I cut to 3.5" long on the mitre saw. It is then ripped in into a 1-1/8" square on the band saw. This square dimension isn't critical, but more of a rough starting size as it will be shaped and squared smaller from here.
I cut the Acrylester and the blackwood to approximately the same dimensions. Then the 1/16" brass and vulcanized fiber spacers.
To bind the different components, I have some 3/8" poplar dowel.
With the Cocbolo in the drill press vise, I bore a hole dead center with a 25/64" bit, This goes in about 2-1/2" inches. The dowel should slip in nicely. I shape the dowel ends to fit the hole as it's not a perfectly flat bottomed hole.
With the vise and same bit I drill the other pieces.
I do NOT drill the all the way through the blackwood ferrule . Only about 1/2 way. See the photo below.
After dry fitting all the pieces, I scuff them with sandpaper and clean them with acetone.
Mixing about 1 tablespoon (15 ml) of West System's G-flex epoxy.
I waited a day and bit for this to harden. If the excess epoxy is not sticky to touch and super hard to chip off, it is ready to start sanding.
Note that cold conditions really slow this epoxy down. Keep it in a warm place while it sets.
The epoxy clogs belts, so I'd rather clog this old belt than a good 2x72" belt on the big grinder.
If you cannot touch it with your bare fingers it has become too hot.
Milling the SlotAs mentioned near the top, it is critical when using this method that your tang is tapered in two dimensions.
Here's the blade for test fitting.
If you are having problems getting the depth you need, try wrapping the blade in a wet rag and clamping it the in the vise.
Heat the very tip of the tang with a propane torch until it starts to glow orange, then immediately push the handle on.
Here is the tang inserted into the handle. There is a small amount of filing with a needle file to shape the opening to accept the curve of the shoulder.
Next, I will mix up some more epoxy, this time about 5ml (1 teaspoon) and add a few drops of black enamel paint. This will blend nicely with the African blackwood ferrule.
Wipe any excess epoxy off with a shop towel or Armor-all wipe.
Your beautiful wa handle is attached and ready to use.