This picture shows the blackwood wedge set at right angles to the grain direction, to prevent any risk of the wood splitting. This is how wedged joints should always be done. The wedge is in line with the head for neatness. All little details....... but they matter.
Here is the batch with the heads all wedged, ready for the cross pins to be drilled. The holes are drilled with a 4.7 mm drill bit and the pin measures 4.76 mm. This ensures a tight fit!
If you want to see a more comprehensive description of the making of my hammers see my article in issue 162 (Jan 2010) of Furniture and Cabinetmaking Magazine. There are many of my articles on line at http://www.woodworkersinstitute.com/