Lay your blade on the inside surface of one scale. Determine the final shape of the blade and tang. Remove excess material as needed.
Again, lay your blade on the inside of one scale and trace the figure of the tang. Using a dremel, remove wood from the inside of one scale so that the tang is flush with the surface of the scale. Drill two holes part way into the scale for the pins.
Take a piece of 1/8" brazing rod or brass rod and make two 1/2" pins for the tang. Sharpen each end so that they will bite into the wood scales. Place the tang into the depression created on one scale, insert the pins into the tang holes of one scale and gently tap into place with a hammer. Place the other scale over the first and gently tap with a hammer to show the pin holes. Remove the top scale and drill shallow holes for the pins.
Cover the insides of the two scales with wood glue. Place the tang and pins into their respective locations and squeeze together in a vice. Use scrap wood between the scales and the jaws of the vise to protect the scales. When the two scales are together, leave the knife in the vise for two hours for the wood glue to cure.