I just finished installing snakewood handle scales on a Misono dragon. Before I started @chiffonodd asked me to take pictures of the process along the way, as he was curious what was entailed. I figured there were probably others on the forum who might be interested in seeing it as well.
This is a much more involved project than replacing a wa handle. I am fortunate to have a pretty well equipped wood shop, otherwise I might not have started doing these. I tried to take pictures of as much of this as I could, but will apologize in advance for the crappy quality of the camera on my antiquated cell phone.
The first thing I do when working on a yo handle is to carefully wrap the knife in paper, then masking tape to protect the blade. Now we are ready to remove the old scales. Most Japanese manufacturers use rivets and glue to mount the handles. The sides of the rivets seat pretty tightly together, but they can loosen over time, which is why you sometimes see gaps developing between the scales and the tang on some older vintage knives on Ebay and such. There are a few ways to get the old scales off, but the method I have found easiest is to use a drill press to drill out the center of the old rivets. It helps to use a punch to mark center to keep the bit from traveling on the steel or brass. A slower drill speed usually works better when drilling metal. A bit of oil helps the bit from over heating
When I do western handles, I use corby bolts and epoxy to secure the new scales. They look like little barbells, with a narrow shaft and 2 larger standard screw heads on each end. They come in stainless steel, brass and copper, in varied sizes, 3/16, 1/4 and 5/16. I like corbys because they offer a good strong mechanical hold on the scales which is much tighter and durable than the epoxy bond alone.
Sometimes the existing drill holes are just a bit to small for the shaft of the corbies, in which instance, they must be enlarged. Some folks prefer a center mosaic pin, which is a straight shaft and will likely require much more enlarging. You can use a needle file to do this. I have a set from Harbor Freight that sold for around $7 I think, but a diamond bit and a dremel tool make this process pretty easy and quick.
Before the new scales are installed, the tang should be prepared for glue. The old adhesive needs to be removed with rough grit sandpaper and acetone.
I failed to take pictures of preparing the new scales. When you buy wood for knife handles they usually come in a single block in a size that is often larger than needed for the scales. I usually try to trim them down so that there is less wood to grind down once they are mounted. Unlike a wa, a western handle must be ground down after they are mounted to tang. This adds a bew challenge to the process. I trim the scales so that they are just thicker than I need, just a little thicker than the bolster. If I want to add some contour, cokebottle shape, to the final handle, I account for that in the thickness of the tang. It is important tha all the cuts on the block are square, otherwise it can really complicate the process of drilling the pin holes. Another thing to mention here, the Misono has a square tang. I have done quite a few tapered tangs lately, where the metal on the hilt end of the tang is thinner than near the bolster. In those types of handles, the handle scale often abutts the bolster at an angle that is slightly more than 90 degrees. If the block is squared, there is a little gap between the scale and the bolster. This must be accounted for when trimming the blocks. The taper also makes it hard to keep the drilled holes straight and true through both sides of the blocks. Thankfully, Misono is factory made and nice and square.
Drilling the scales for corbys is a 2 step process. First, holes are drilled to fit the shaft of the corbys. I usually drill the hilt end first, then use a pin to hole the scale in place while I drill the other 2.
The next step is to flip the scale over and drill a slightly larger hole to accomodate the slightly larger head of the corby. Depth here is very important. It must be drilled deep enough so that the female end of the corby shaft goes into the tang holes so that the male threaded end can screw in, but not too deep or the corby will fully tighten before it can pull the scales tightly to the shaft.
This is a much more involved project than replacing a wa handle. I am fortunate to have a pretty well equipped wood shop, otherwise I might not have started doing these. I tried to take pictures of as much of this as I could, but will apologize in advance for the crappy quality of the camera on my antiquated cell phone.
The first thing I do when working on a yo handle is to carefully wrap the knife in paper, then masking tape to protect the blade. Now we are ready to remove the old scales. Most Japanese manufacturers use rivets and glue to mount the handles. The sides of the rivets seat pretty tightly together, but they can loosen over time, which is why you sometimes see gaps developing between the scales and the tang on some older vintage knives on Ebay and such. There are a few ways to get the old scales off, but the method I have found easiest is to use a drill press to drill out the center of the old rivets. It helps to use a punch to mark center to keep the bit from traveling on the steel or brass. A slower drill speed usually works better when drilling metal. A bit of oil helps the bit from over heating
When I do western handles, I use corby bolts and epoxy to secure the new scales. They look like little barbells, with a narrow shaft and 2 larger standard screw heads on each end. They come in stainless steel, brass and copper, in varied sizes, 3/16, 1/4 and 5/16. I like corbys because they offer a good strong mechanical hold on the scales which is much tighter and durable than the epoxy bond alone.
Sometimes the existing drill holes are just a bit to small for the shaft of the corbies, in which instance, they must be enlarged. Some folks prefer a center mosaic pin, which is a straight shaft and will likely require much more enlarging. You can use a needle file to do this. I have a set from Harbor Freight that sold for around $7 I think, but a diamond bit and a dremel tool make this process pretty easy and quick.
Before the new scales are installed, the tang should be prepared for glue. The old adhesive needs to be removed with rough grit sandpaper and acetone.
I failed to take pictures of preparing the new scales. When you buy wood for knife handles they usually come in a single block in a size that is often larger than needed for the scales. I usually try to trim them down so that there is less wood to grind down once they are mounted. Unlike a wa, a western handle must be ground down after they are mounted to tang. This adds a bew challenge to the process. I trim the scales so that they are just thicker than I need, just a little thicker than the bolster. If I want to add some contour, cokebottle shape, to the final handle, I account for that in the thickness of the tang. It is important tha all the cuts on the block are square, otherwise it can really complicate the process of drilling the pin holes. Another thing to mention here, the Misono has a square tang. I have done quite a few tapered tangs lately, where the metal on the hilt end of the tang is thinner than near the bolster. In those types of handles, the handle scale often abutts the bolster at an angle that is slightly more than 90 degrees. If the block is squared, there is a little gap between the scale and the bolster. This must be accounted for when trimming the blocks. The taper also makes it hard to keep the drilled holes straight and true through both sides of the blocks. Thankfully, Misono is factory made and nice and square.
Drilling the scales for corbys is a 2 step process. First, holes are drilled to fit the shaft of the corbys. I usually drill the hilt end first, then use a pin to hole the scale in place while I drill the other 2.
The next step is to flip the scale over and drill a slightly larger hole to accomodate the slightly larger head of the corby. Depth here is very important. It must be drilled deep enough so that the female end of the corby shaft goes into the tang holes so that the male threaded end can screw in, but not too deep or the corby will fully tighten before it can pull the scales tightly to the shaft.
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