Introduction: How To: Make a Belt Knife
In this instructable I will be making a small belt knife for every day carry.
This particular knife is for maker legend Jimmy Diresta. Jimmy has been a friend for a number of years and recently helped me get a jump start on my new youtube channel. (www.youtube.com/makeeverything)
Check out the video below showing how I made this knife. And for a detailed write up of the process continue into this instructable! Enjoy!
Step 1: Design, Layout, and Template
The belt knife is something that I designed a few years ago. I have a small knife brand called “Timbered works” (www.timberedworks.com) and before i opened my maker space (www.makeeverythingshop.com) I was making and selling these knives fairly often.
I decided to refine my original design and model it on the computer so I would have areliabel paper template to make more of these knives with.
Drawing knives in sketch up is relatively easy but you can totally skip this step and just sketch the knife in permanent marker on the steel.
A paper template is nice because it has a fine line you can follow and you can replicate it as many time as you want. I use Super77 spray adhesive to attach the template to the steel. The steel I'm using is CPM 154.
Once the template is glued on you can use a center punch to transfer the drilling locations into the steel.
Step 2: Drilling the Finger Holes
CPM154 is a relatively tough steel even before its hardened. Because of this you want to use high quality hole drilling tool to get the 7/8” finger hole in the blank.
The cutter I'm using is called an “annular cutter” its basically a heavy duty 1 piece hole saw with carbide teeth on it. These are common in the ironworking work and they work GREAT for drilling in steel.
NOTE: the cutting oil i used totally dissolved the spray adhesive and made me lost the template, but thats okay.
Step 3: Cutting the Initial Shape
Since i lost my paper template during drilling i had to improvise and try and re-attach it so I could trace the shape. This worked fine.
On my portable bandsaw i cut the shape close to the line I drew, and then on the 2x72 grinder I refine the shape closer to the line with a 120grit zirconium belt.
Step 4: Adding the Bottle Opener Notch
I like to incorporate a bottle opener on my knives, the particular shape of the bottle opener is something that I've designer through trial and error.
Im not going to go too far into detail on how I achieve a functional notch, but I will say I start with a 3/16” hole, and using 2 properly spaced straight cuts and some file work I achieve a minimal, yet functional opener.
Step 5: Scribing and Laying Out the Bevels
Now that the shape is refined and the bottle opener notch is in its time to prepare to grind the bevels of this knife. In order to scribe the center of the blade I cover the blade with red Dykem layout fluid. Dykem is a necessity of any metal shop, if your not using it, you should be.
The blade material is 1/8” thick, so I use a 1/8” drill bit to scribe the exact center of the material on a granite surface plate. I hold the blade and the drill flat to the surface and then run the blade across the point of the 1/8” drill. The point of the drill scribes a line in the layout fluid that I can use a reference when I'm grinding. To be sure the line is centered, i flip the blade over and scribe with both flats of the blade as a reference against the granite plate.
To lay out the bevels I use a caliper and allow the pointed edge to scribe into the layout fluid. (Machinists look away!)
Step 6: Grinding the Bevels
There are a million and one methods for grinding knife bevels. I am not an expert grinder, its something I struggle with and am constantly learning to get better at.
My process involves using plunge guides attached to my blade in order to keep the bevels even on both sides. For a blade this small I DO NOT use an angle jig, I grind the bevel angle freehand.
I start with a 120 grit zinc belt and then move up to a 220 grit silicon carbide belt.
Consistency is key here, you want the bevels to look symmetrical on both sides of the knife. For me this is a challenge every time, but see these links below for some great information about grinding knife bevels:
Step 7: Adding a Sharpening Choil
A sharpening choil is a little rounded cutout at the edge of a knife blade where it meets the plug lines, this allows a sharpening stone to travel to the end of the sharpened edge without hitting the plunge. Some people like these, others do not. I deed to add one once I saw the blade ground.
To add this I use a little “metal router” that I have set up. Basically this is a carbide single cut burr mounted inside a palm router. This works GREAT for adjusting metal parts. I have to thank Mike from Gavko knives (http://www.bladehq.com/cat--Gavko-Knives--1752) for this idea.
Step 8: Stamping in a Makers Mark.
Since this knife is a gift for Jimmy Diresta I decide to stamp his name in the blade. Typically I just stamp a “Z” in my blades as my personal makers mark.
I use 1/8” letter stamps and am especially careful as I lay them out in the steel. You only get one chance at this so TAKE YOUT TIME.
Step 9: Final Profiling of the Blade
Before we heat treat the blade I want to make sure all the burrs and sharp edges are gone. I will be able to do some grinding on the blade once its hardened but I like to get as much done as I can prior to heat treat. I use a Dremel to smooth out any rough edges and get it looking good before I put it in the oven.
Step 10: Heat Treating
CPM 154 is a more complicated steel to heat treat than most “amateur” steels. To heat treat CPM154 the blank has to be put inside an air tight stainless steel foil packet. The foil is razor sharp and I am especially careful not to cut myself on it. Once i get the blade wrapped I use a little arbor press to make sure the folded edges are nice and tight. The oven I'm using is a:
And the recipe I use for heat treat is:
Fast ramp up 1450F, soak 10 minutes, continue fast ramp to 1925F, soak for 30 minutes. ( you will need a programmable heat treat oven for this)
If you don't have a way to heat treat a steel like CPM154 I suggest you sent it out to a professional heat treat service. I have used Peters heat treat in the past, they are great people, very helpful, and their turn around time isn't too bad. http://www.petersheattreat.com
While the oven is cooking (80 minutes) I will start to make the leather sheath!
Step 11: Leather Sheath Layout and Cutting
Since the belt knife is something I have made many time I already have a reliable pattern for the leather sheaths. If you making a knife for the first time, you'll want to make a slightly oversized pattern BEFORE you put the knife in the oven. (or you'll have to wait until its finished)
I trace my pattern on this piece of brown leather and cut it out with a sharp knife.
Step 12: Making the Brass Belt Clip
I misplaced the template I had for the brass belt clip I usually attach to my leather sheaths so I had to model it off of my personal EDC belt knife. This is a good exercise in improvising. I measured what I had on my current knife and replicated it on a pieces of 1/16” thick brass stock.
I use an arbor press and a little rounded steel “die” to press the clip into a 180 degree turn. Then I take it over to the anvil and use a smooth faced hammer to refine the shape and get the bends the way I want them.
The purpose of this clip is to sort of lock into a persons belt so the knife doesn't accidentally fall off.
Step 13: Stitching Up the Sheath
With the belt clip finished I can lay it out on the sheath and then glue up the leather.
I glue and clamp the leather and give it time to dry before I start punching the sticking holes.
Luckily this sheath is small so punching the stitching holes is pretty quick, then I use wax thread to stitch the sheath together. The last pass of the stitching gets a square knot and rivet to lock it in place.
Step 14: Adding the Retention Strap
Once the sheath is stritched up I will add a snap on the little strap that holes the knife in the sheath.
Step 15: Complete the Knifes Heat Treat (Plate Quench) and Temper
CPM154 isn't quenched in a liquid like a high carbon steel. CPM154 is “Plate quencehed”. Basically the knife is pulled out of the oven at 1925F, and put in-between two 3/4” aluminum plates. I stand on the plates to apply weight, and then shoot compressed air in-between the plates. This keeps the blade from warping, and cools it very quickly.
When this process is complete the knife is VERY hard, and needs to be tempered.
Tempering is the process in which the knife is made slightly less hard, so that it has durability, but also stability.
The tempering process I used for CPM 154 is 425 degrees for 2 hours, 2 times.
Step 16: Cleaning Up the Finished Blade
Now that the blade has been heat treated and tempered its time to finish up the grinds and flats.
I use a 220 grit belt to remind the bevels, and then I use a scotch bride belt to apply a uniform brushed look.
I switch over the Dremel and use a little switch bride wheel to clean up the inside radius of the finger grooves.
Step 17: Stonewashing the Blade
“Stonewashing” is a popular blade finishing technique. It gives an interesting darkened look, and I prefer it for a heavy use knife like this. To stonewash I first soak the knife in straight PCB etchant solution (acid)
I let it sit in the acid for 30 minutes, then take it out and wash it with soap and water.
Once its clean and dry its noticeably dark from the acid eating away at the surface.
Now it goes into a rock tumbler for about 15 minutes. The rock tumbler polishes the high spots of the acid etched face and gives it a random pattern.
There are many ways to add a forced finish or patina to a knife and I encourage you to experiment and find one that you like.
Step 18: Final Sharpening
Now that the blade is stone washed its time to add the final edge. I start here with a 600 grit belt on a 1x30 belt grinder. Then I move to a 15 micron belt to bring the edge to a sharp apex. I then switch to two leather strops, the first with black buffing compound, and then finally to a strop with green compound.
This process leaves you with a mirror polished edge that is VERY sharp. It will easy shave hair and slice paper.
Step 19: Oiling the Sheath
Last but not least, I add a little neatsfoot oil to the leather sheath to act as a protectant and water repellant. This also darkens the leather and furthers the contrast between the leather and the brass. I love the look of this.
Step 20: Admire Your Knife!!
You did it. This little knife is a great utility carry. Its short enough to act as a mini prybar, but sharp enough to cut your way out of a tough situation. I carry mines on the back of my waistline, and I've used my personal EDC belt knife for 3+ years.
This particular knife was for maker legend Jimmy Diresta (www.youtube.com/jimmydiresta), to say thank you for helping me get a start with my youtube channel. You should follow him on youtube if you don't already.
Thanks for sticking through this instructable. Please check out my youtube channel for a detailed build video. If you have questions, ask them in the comments!
If you want a belt knife, I am offering them for sale on my website:
Participated in the
Makerspace Contest 2017