How to Make a Knife From a Kit

Jul 02, 2023

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We built a classic folder in about two hours.

It’s always good to learn new things. The other day I discovered that it’s fun to build a knife.

I received a $40 kit of parts from knifekits.com. Tucked neatly inside the box was also a single sheet of general instructions with an exploded illustration of the knife to be built. I went from loose parts to a well-executed knife in about two hours.

The tools I needed were a pair of locking pliers, a ball peen hammer, a bench vise, and a random orbit sander. I’ve linked to those tools below and I also show a Dremel rotary tool. I could see where that might be a help, but you can build a knife without it. Chances are pretty good that you already own what you need to build a knife from such a kit.

The knife I ended up with is a good first effort. It’s not perfect, but it is neat, attractive, and its blade folds smoothly. Equally as important to those features is that the knife’s blade locks securely and safely. I didn’t labor over every detail to perfect this project. Rather, I sped through the job in an effort to know whether such a kit quickly produces an attractive knife that functions well, or whether the process is overly fussy and unrealistic for an amateur knife maker.

Although this is just a basic beginner’s knife, my sense is that these kits are a fun and fast way to produce an inexpensive custom knife. It’s also a great introduction to the craft of knife making. And, furthermore, you don’t need to be an expert craftsman to do this.

Here’s an overview of the process and some links to help you secure needed tools and materials.

I wanted a basic folding knife for my first project. Building one of these from a kit comes down to this: pin the parts together, peen over the pin heads, and grind the rough assembly smooth using a random orbit sander. I’m oversimplifying, but there’s really not much more to making a basic knife than that.

In more detail, a lock back folding knife consists of a blade, a spring (the back spring), a latch (called the rocker arm), two handles (the scales), and two sides (the side plates). The side plates, rocker arm, back spring, and blade are the core of the knife.

To assemble the knife, you take the blade, back spring, rocker arm, and the right side plate and hold them together with pins and a clamp or locking pliers. Fit the remaining pins through their holes and slip the left side plate into position over the pins.

Place one scale at a time over the pins on each side. Tap down on the scales to mark the location of the pins on the bottom face of the scale. Drill the pin holes in the scales. Fit the scales over the pins (see my note below on using epoxy), and peen the ends of the pins down into the wood, locking everything together.

Grind everything flush and smooth with a series of abrasives. I used 80, 120, 140, 180, 220, and 400 grit discs. I finished with a little hand sanding using 800 and 1000-grit abrasive paper.

The instructions called for using epoxy between the side plates and the scales. I could see where this would provide a little extra insurance to hold everything in place. I used a few dots of super glue to speed the process. When the adhesive had cured for a few hours, I picked up where I left off, peened the pins down against the wood and ground everything flush and smooth.

After the knife parts were riveted together, I simply sanded all the parts smooth and flush using a random orbit sander and a sequence of coarse to fine abrasives.

Place a rubber non-slip mat on the bench to hold the knife in place while you work over its face and edges with a random orbit sander.

A small C clamp (or locking pliers) is useful to hold the knife parts together while you mark the location of the pins on the handles.

If you don't have a small C Clamp to hold the knife parts together while marking the pin locations, use a pair of locking pliers.

A small ball peen hammer with a 12-ounce head is all you need to peen over the rivets that hold the knife together.

We can see how a Dremel can be an extremely helpful knife-building tool. It's the kind of tool that isn't necessary but, depending on the knife you're building, it can probably speed everything from trimming down pins to trimming down wood handles.

The instructions for building this knife tell you that there are many ways to do this job. I believe it. When the pins had been peened over, I had a hunch that the simplest thing to do was to lay the knife down on a perforated non-slip rubber pad and grind everything (sides, back, top and bottom edges) flush and smooth with a disc sander. Whether it was beginner’s luck, I can’t say, but that’s exactly how it all worked out.

I learned a few other things. First, peening the pins down is what provides the clamping action that holds the blade, plates, scales, back spring, and rocker arm together, but it's easy to get overzealous while hammering. This creates too much clamping force against the blade and can cause it to be too difficult to open or close—or both. To prevent that, the manufacturer provides some very thin shim metal. You insert this between the blade and the side plates during riveting. The shims prevent an overly tight fit. But you can still over do it, and that’s exactly what I did. To correct this, I had to force the shim stock back into place and work the blade back and forth to get a proper pivoting action. You want the pivot action to be firm but not tight.

Finally, don’t get carried away with the orbital sander. Grind, check your work, change the knife’s position, and remember to work both sides of the knife equally.

Roy Berendsohn has worked for more than 25 years at Popular Mechanics, where he has written on carpentry, masonry, painting, plumbing, electrical, woodworking, blacksmithing, welding, lawn care, chainsaw use, and outdoor power equipment. When he’s not working on his own house, he volunteers with Sovereign Grace Church doing home repair for families in rural, suburban and urban locations throughout central and southern New Jersey.

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