Making Custom Chef Knife With 3d Printer : 9 Steps (with Pictures)

A year ago my girlfriend and I started a foodblog called Yue'sFoodStory, Our focus is spread California food culture( Sustainable, Healthy, Local sourced) to Chinese communities. a year later, we have grown to have 50k followers. here is her instructables

https://www.instructables.com/member/YuesFoodStory/

Making my own kitchen knives have been on my mind for a while. that After reading the post on

How to make Knife handle by Gabe

https://www.instructables.com/id/Make-custom-Knife-...

I felt like it is not difficult at all, with the access of tools and machines. My goal is to make a knife as close to professional standard/look as possible. this instructable shows from a clay model to prototype model to the final finish product.

Step 1: Make a Prototype Model

Before my foray in to the knife making world. I visited custom knife shop knife in the city, the bladesmith told me the process of making a custom knife. it is an art form and I really didn't have too much time and energy to learn all the skills.

the best way is to purchase a knife blank that is already hardened and ground, then work from there. I bought my blank from USAKnifemaker http://usaknifemaker.com/. before it arrives I started design the rest of the component.

First of, with the measurement of the blanks that written on the site. I sketched the outline on illustrator. then use laser cutter to cut them out of 1/8 in plywood. this batch I cut two 8" chef, one 6" chef and one 4" pairing knife.

I then formed the handle with modeling clay. It is very easy to work with modeling clay, so I made sure the shape is ergonomically accustom to my hand. after some finesse with the clay I wiped rubbing alcohol to make the surface smooth.

Step 2: Record the Measurement , Design the Handle

Once the handle is smooth and centered, and the grip feel perfect . I start to measure the dimension of the handle. I picked 4 points along the handle and record the dimension of the cross section. there is a slight curve and slightly bigger in the middle.

I use these number to model the handle in 3ds Max. started with 4 boxes that have the dimensions that I recorded. then join them to form the rough shape of the handle. I use turbosmooth with control loop to achieve the smooth finish. This is my way of doing it, and it worked really well.

use the shell modifier to make it hollow then I split the model in half and prepare the mesh to be 3d printed.

Step 3: 3D Printing the Handle

the handle is 3d printed on Objet connex 500. I used a clear resin so I can see the logo once I have it printed as well.

The logo is a calligraphy of Yue's Food Story written in Chinese. I wrote it when I was back home last summer. then I export it in gray scale to Zbrush and used the shadowbox feature to create a 3d rendition of the logo. 3d printed in black.

meanwhile the stainless steel knife blanks have arrived, the handle on the blank was too big so I had to grind it

Step 4: Grind N Polish the Blade

wrap the blade then I used metal grinder to grind off the handle, hardened metal is hard to grind but with a little patient it was going smooth. then I polished the blade with wet sand paper. from 180 all the way to 2000grid. lastly, polished the blade with polishing compound. the end it is a mirror finish blade.

Step 5: Engraving the Blade

I use cermark metal engraving ink. just sprayed on the blade and laser engraved the graphics. after it is done. rinse off the spray in water.

Step 6: Making the Mold for Handle N Cast

I spray clear coat on the 3d printed parts to make the surface glossy. then assemble the knife, seal the gaps with modeling clay and wrap the blade in blue tapes.

I made a platform just to expose the handle then I used cardboard to make a tube. the tube is a bit bigger than the handle. then pour in silicone. here I used Mold Star 30

Once the silicone is cured, cut it open and take out the 3d printed parts. wrap rubber band around the mold to ensure it is sealed. mix epoxy resin and pour it into the mold. the epoxy i m using is a non yellowing low toxic high quality epoxy.

Step 7: Final Product

the swirl finish is achieved when I first pour 90% of clear resin ( nothing added) then the last 10% I pour resin mixed with mica powder. leave the mold un disturbed overnight. when I opened the mold the swirl effect naturally formed. Knife is very sharp after honing.

Step 8: Packaging the Knives

I thought it is not done without a good case, so just quickly designed a box on http://www.makercase.com/ laser cut the patterns on 1/8" plywood then glued them together. sand it with 400 grits to bring out the wood grains then fill the inside with micro clothes for the knife to rest.