I’m finally within striking distance of finishing this pair of William Henry knife scales. It’s now time to inlay the 24 karat gold accents.
Above, I’m beginning to inlay the stamen area of a cherry blossom. I start by carving a deep depression in the center with my smallest carbide bur in my NSK grinder. This bur is about a quarter of a millimeter in diameter, so that should give you an idea of how tiny the cherry blossoms are.
Next, I need to undercut the bottom of the depression so the gold will have an undercut area to flow into when I pound it in, thus being “captive” in the metal. Since this depression is so tiny, there isn’t enough room inside to use anything but a very narrow punch. You can see a side view of the little sharp ended punch, along with a detail view I altered to try and make the geometry a little clearer. I make these from broken or worn out carbide bur shafts (the shafts are high speed steel). The large face is ground in at 30 degrees, with about a ten degree smaller bottom angle, so the entire angle is about 40 degrees. I simply drive the punch in the bottom edge of the hole at a low angle, which cuts a depression. I continue doing this all around the circle, leaving a groove completely around the bottom.
Above, a diagram of the process, hopefully a little clearer than my verbose explanation.
Here is a piece of 30 gauge 24 karat gold wire. It’s a little on the small side for this circular inlay, so I’ve used an old engraver’s trick to make it a little larger by melting a small blob on the end. This also serves the purpose to automatically anneal the gold making sure it is soft enough to flow into the undercuts.
And, above, I’ve used a small brass punch to pound the gold into the cavity. I use a brass punch because it is hard enough to drive the gold, but soft enough not to damage the steel around the inlay cavity. You can see the gold has stuck, because I’m no longer holding the wire and it is held fast. Now I’ll use a sharp blade to carefully cut the gold wire free.
A close up view.
Above you can see two inlays in, and the business end of my little brass punch.
I use a slightly rounded steel punch to finish the inlay. You can see the punch above, and the thin gold leaf remaining after further punch use. A little work with a small scraper to get rid of the waste and the inlay will be complete. If you want the gold to be shiny, this is the time to use a burnisher to smooth the surface. I tend to like the raw look of the gold, so I’ll leave it a little rough. Microscopically rough, of course.
Above, three finished inlays after the scraper has visited them.
Now that the blossom inlays are complete, I need to add a few little gold accents to the butterfly wings. This process is similar to the previous inlays, except that the pockets are a little larger. I use a tiny flat graver to raise a forest of burs in the bottom of the pocket to further help trap the gold, and use the same bur/chisel punch to undercut around the bottom that I used for the blossoms. These are still pretty small inlays, but I’ll bend the 30 gauge wire to fit the pocket. After bending, then annealing, I’ll pound the gold into the inlay. High karat gold like this will cold weld to itself and form a solid chunk quite nicely, as long as I keep everything really clean.
And, above, stuck fast after using the brass punch. I’ll use the steel punch, and then scrape the inlay flush as before, being extra careful since the shibuichi butterfly wing is much softer than the steel of the knife scales.
And, finally, I’ve added my special process of patinating the 416 stainless steel in the shishiaibori carved areas. The scales are finally complete. I’ll send them back to the William Henry knife studio for final assembly, and hopefully then they will move on to become a family heirloom of some lucky customer.
Thanks for Looking!