Making Wood Knife Handles, Finish And Fit
The handle of your new Custom Knife will likely be the first thing people notice and touch. They might comment on the shape of the blade, how "shiny" it is, or how sharp. But the handle will capture them. They'll turn it in their hands a few times as if they're memorizing the grain and contours.
The first four pictures attached here show different pieces of Flame Box Elder, from a raw green log to a kiln-dried and stabilized wood block, then that same block sawn and book matched as knife "scales," and finally that block again as a finished knife handle. I chose Flame Box Elder for this article because the bright red streaks help keep our eyes oriented to the block as it goes through the different processes. This has both nothing and everything to do with putting an attractive handle on a Custom Kitchen Knife. If the wood isn't properly dried, professionally stabilized, sawn in the correct orientation to the grain or color, book-matched, glued, pinned, and finished, a beautiful piece of wood is ruined, and we get to start over.
I will try below to describe what happens at Keith Nix Knives. I have no idea what other people do. So let's get started!
1- Why use stabilized wood? What is stabilized wood, and how do you do it?-Stabilized wood knife handles have undergone both vacuum and pressure to force a liquid polymer resin completely through a block of wood into every pore and crevice. It is then heated to a specific temperature until the liquid "polymerizes" or becomes solid. At this point, the wood knife handles are no longer porous and become impervious to the shrinking and swelling associated with changes in humidity. This is especially important for kitchen knives in a professional, wet environment. The stabilized knife handle won't absorb the sometimes yucky stuff it comes in contact with when working in the kitchen, or field dressing fish or game.
Here's a short piece about selecting handle Materials
2- Sawing the block-
I usually send my wood to K&G for stabilization, typically as 2x2x12" blocks. When they return, I can saw that block into four wood knife handle blocks of 1x2x5"—at this point, looking at your blocks, studying the grain, and determining which of those 2" flats you want to be the faces of your handles is essential. Nearly always, the grain on one side will be curlier, burlier, more twisted, or have some attractive color variation than what you see on the adjacent sides. Ensure you saw your block, so the pretty sides are OUT on your knife! Making book matched handle scales for a knife maker involves selecting a piece of wood with interesting grain patterns and color. The wood is cut in half lengthwise and carefully matched to ensure the two sides are mirror images of each other. We then sand and shape the handle scales before fitting them to the knife tang. The result is a stunning, symmetrical handle that showcases the natural beauty of the wood grain and color.
I like to start with two knife scales or sides about .450", or just over 7/16 thick. I use a bandsaw to split a 1" block in half and have a little wood to spare for sanding, flattening, and such. Afterward, we will have two blocks that are .400-.420" thick, 2" tall, and 5" long. Plenty of wood for the handle we're about to make!
3- Flattening the Scales-
After sawing and book matching the two scales of the wood knife handle, it is necessary to make each scale flat and parallel to attach to the tang of the knife without gaps and voids. This also helps with drilling the pin holes perpendicular, straight, and to the proper size.
I use the 2x72 belt sander and a 9" disc sander for this operation and check for flat and parallel on a granite surface plate and with digital calipers or micrometers. I can't stress enough the necessity that the side of the scales glued to the tang is FLAT. If not, there will be gaps in your scale/tang joints.
I use liners made from G10 or Micarta between the wood and tang of my knives. It is an aesthetic feature and serves no practical or structural purpose. Liners add a bit of color to the handle as a whole. To me, liners bring the whole handle together as a unit and offer some color contrast to the wood and steel.
I primarily use G10 for liners in the .045-.060" range. The shop has several colors in stock, but I lean toward black or deep cherry red for nearly all knives. The material only needs to be roughed up with 100-grit sandpaper for better glue adhesion, and it's ready to go.
I use a small benchtop drill press for drilling pin holes. I clamp one scale half, liner, and tang together and transfer drill the handle holes right through the tang holes in the blade. This ensures a good lineup and saves the need for a mill and digital readout. I use 1/8 pins, so I drill with a #32 drill (.116) and follow that with a .1250 reamer. This makes for a snug hole for the pins.
6- Rough Sanding-
Once the pin holes are reamed, I dry fit the handle to the knife tang and belt sand a rough finish, making sure to get a good start on the contours of the handle, breaking all sharp corners down to gentle contours. After this, I disassemble the knife handle and put it back together without the knife. This step is to shape, sand, and finish the front of the scales where they meet the knife at the ricasso. Once glued, finishing this part of the handle would be impossible without scratching the already polished blade with sandpaper.
7- The Glue Up-
Once the holes are drilled and reamed, we can glue the handle to the knife's tang. I use West Systems "G-Flex" epoxy glue because it retains some flexibility even after it sets and cures. I apply a thin coating to all mating surfaces, the scale, liner, pins, and tang. The pins are dipped in epoxy and worked back and forth through the pin holes to ensure a good epoxy coating inside the holes. It's crucial to have already finished sanding the front of the handle scales. (See #6 above) Don't forget this step!
Once the handle is glued and assembled, I use two or three "quick clamps" to LIGHTLY squeeze the handle scales to the tang of the knife and secure them until cured. An important note here is not to clamp too tightly. Doing so creates the possibility of squeezing too much glue out of the joints, causing a GLUE-STARVED JOINT. Just don't do it.
After clamping, there will be glue seeping out of all your joints. Gently rub all this away, especially from the FRONT of the handle where you've already finished the wood. Isopropyl alcohol is a suitable solvent for wet epoxy. Be sure not to rub too much on the front, as the alcohol can erode the epoxy from under the front of your scales, leaving an empty joint!
8- Finish Sanding-
G-Flex epoxy is a 24-hour cure glue, so give it time to set and cure thoroughly. After that, it's back to the belt sander for some final shaping and removal of "squeeze out," or the excess glue leaked out of the joints due to clamping. Next, I use a half-sheet handheld orbital flat pad power sander. I start with 120 grit and smooth the handle to its final shape. It's pretty quick work if you apply a little pressure! Be careful not to create deep gouges by over-sanding in one spot.
After the 120 grit, I usually jump to 400, then 800, 1000, 1500, 2000, and finally 2500 grit for a final finish. Once to 2500, the professionally stabilized wood will take on a luster and shine like it already has a coat of satin or semi-gloss finish. Because the wood is stabilized, there is no need for any other finish at this point. A coat of paste wax and a good buffing is all it needs!
If your wood knife handles material is one of the wood types with large pores like oak, walnut, or chestnut, I suggest wet sanding at 400-600 grit with thin CA glue (Super Glue). The glue will catch microscopic bits of wood dust; the sanding will force the glue/dust into the pores and fill them. Once you have filled all the pores, continue sanding as usual.
9- The Finish-
If the customer does want a high gloss knife handle finish, I apply two to three coats of Tru-Oil gun stock finish, a blend of boiled linseed oil, varnishes, and hardeners that dries faster than pure linseed oil. Tru-Oil makes a very durable waterproof finish that is EXTREMELY glossy. A 4-ounce bottle will do dozens of knives if you apply it with a gloved finger, rubbing vigorously to ensure the oil is worked down into the pores.
This is a quick and dirty list of the steps required to attach a handle to the tang of your kitchen knife and make the grain and wood color stand out in a beautiful and satisfying way! Or you can choose an "All Synthetic Handle."
More FREE Learning:
Learn About Stabilizing Wood HERE!
Click here to learn about knife steel properties and how alloys alter them!
Click here to learn about kitchen knife types and styles.
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Thanks for reading,