When I first started making handles for Japanese knives I didn’t have access to many product examples to compare so I searched the internet for a sizing chart of sorts. It turns out there wasn’t a very detailed one. The best I could find was mainly just “length of handle versus length of blade”, but it didn’t get into any specifics. I kept searching and found pieces of information here and there until I pieced together some good proportions to start testing. You find out pretty quick on prep-heavy days what works and what doesn’t. After a lot of personal experimentation and feedback from others in the kitchen these are my go to dimensions for a Gyuto / Chef knife:
Octagonal Wa-Handle Dimensions
Blade length: 210-270 mm
Handle length: 135 mm
Ferrule end width: 18 mm
Ferrule end height: 23 mm
Butt end width: 20 mm
Butt end height: 26 mm
Chamfers: 5 mm marked in from corner.
I find these dimensions work well for a few different reasons. The handle is big enough to house the tang of the knife without becoming structurally weak or feeling too bulky. The slight taper toward the blade is balanced and gives a good secure grip without giving the feeling your hand is creeping forward. The handle is a good length for fitting a wide range of hands but not long enough that you find it hitting your wrist when doing detail work with the tip of the blade.
Shaping an Octagonal Wa-Handle
I like to use all natural wood for my knife handles, in my opinion there is no substitute for the feel of natural wood for a tool handle. The method for shaping that I’ll be showing here doesn’t require a bunch of fancy machinery or expensive tools.
This method of construction differs from the slotted dowel method I have previously posted about. In this method you drill a hole in the body of the handle just big enough to fit the tang. You can then either drill a matching hole in the ferrule and use a short dowel plug or use some alignment pins for extra strength between the body and ferrule. Then after glue up I mark and drill out the tang slot. I find this method results in a tighter and cleaner fit.
I should mention that I make the butt end and ferrule end square (90 degrees) to the top of the handle. This makes the top of the handle in line with the spine of the knife and the bottom face of the handle taper up toward the blade. Both sides taper in from the butt end toward the blade. I account for all of this when doing my layout, which is why you’ll notice my tang slot is up from centre at first.
After glue-up I like to take a couple shavings off the top face of the handle to give me a good reference point for marking out the centre of the handle along with the tang slot.
Once I’ve established centre and marked the tang slot I drill out some pilot holes to start the slot.
At this point I start connecting the pilot holes using the drill at an angle. After that I move on to digging it out with a jig saw blade held with a small pair of vice grips. Then square things up and refine the slot with some small files.
Once the tang is tightly fitted, I begin layout of the handle shape. I find it better to fit the blade before shaping the handle so that when making the tang slot, if I go slightly out of square I can easily adjust the layout to account for it. Going the other way (shaping the handle and then cutting and fitting the tang slot) means it needs to be 100% perfect out of the gate or you’re going to have spend a great deal of time tweaking the fit. More than likely you’ll end up having to bin the handle because you’ll end up with a skewed fit or a slot way bigger than intended.
Working from my top reference face, first I mark the 18 mm wide, 23 mm tall ferrule end, followed by the 20 mm wide, 26 mm tall butt end.
Now I just plane down to my layout marks and I have established the dual taper of my handle.
Some people only eyeball the chamfers but I find it beneficial to have a visual aid of what I’m shooting for. It can be pretty difficult to mark out the chamfers accurately, which is probably why most people do only eyeball it. I made a handy little guide out of a scrap piece of walnut that gives me perfect 5 mm chamfers every time.
Once I have my chamfers marked I use my hand plane to remove material down to the line. I hold my plane in one hand and essentially use it like a mandoline (kitchen tool). The most import thing is to pay attention to grain orientation. It can look a bit wonky and be harder to keep track of once you’ve started. Lose track of it and you will quickly ruin your handle and have to start over.
At this point I’ll lap all the faces on a 320 grit sanding block. Then I’ll sand a small chamfer on the edge around the butt end and the ferrule end. This handle is now ready for finishing. My go-to for finishing woods that aren’t naturally water resistant is 100% pure Tung oil, followed by my custom wax polish.
I use epoxy to mount the blade and this knife is now ready to be put to work.