Half of the first call on a new knife project goes on agreeing what to call things. One person says bolster and means the guard. Another says liner and means the scale. Nobody is wrong, but the drawing and the quote need one word for each part.
These are the names most knife factories use, ours included, on drawings and inspection sheets. The two diagrams use knives from our own Open Design library.
Parts of a folding knife
The photo shows what you can see from outside. The tip is the point, the spine is the thick unsharpened back, and the edge is the sharpened side. The curved part of the edge toward the tip is the belly.
The blade turns on the pivot. On this knife you open it with the flipper tab, a small lever that sticks out of the back of the handle when the knife is closed. Other knives use a thumb stud, a thumb hole or a nail nick for the same job.
The handle scales are the outer panels, one on each side. The pocket clip is screwed to one scale, and the lanyard hole sits at the butt end.
The parts that decide how a folding knife feels are the ones you can't see in the photo:
- Liners: thin metal plates under the scales that form the frame. Some knives have no separate liners and the scales do the work.
- Lock: what holds the blade open. In a liner lock, part of the liner springs across behind the blade. A frame lock does the same with the handle itself. A lockback uses a bar along the spine.
- Washers or bearings: sit on either side of the blade at the pivot so it turns smoothly.
- Detent: a small ball that holds the blade closed until you push past it.
- Stop pin: the pin the blade rests against when it is open.
- Backspacer or standoffs: hold the two sides of the handle apart at the back.
Parts of a fixed blade knife
A fixed blade has no mechanism, so the list is shorter. The blade terms are the same: tip, edge, belly and spine.
The grind line is where the bevel meets the flat of the blade. Follow the edge back toward the handle and you reach the ricasso, the flat unsharpened section where a logo usually goes. The finger guard stops a hand sliding forward onto the edge.
The steel doesn't stop at the handle. The part that runs inside it is the tang. On a full tang knife it is the full width and length of the handle, with a handle scale bolted to each side, and you can see steel all the way round the handle's outline. A hidden or partial tang is narrower and sits inside a one-piece handle. The end of the handle is the butt, which often has a lanyard hole.
Most fixed blades ship with a sheath, and it is part of the product. Its material and how it holds the knife belong in the spec from the start.
A few more blade terms
These come up on drawings for both kinds of knife.
- Grind: the shape of the blade's cross-section. Flat, hollow and saber grinds are the common ones.
- Swedge: a bevel ground into the spine near the tip. It is not sharpened.
- Jimping: small notches cut into the spine or the handle for grip.
- Choil: a small cutout where the edge ends near the handle. It lets the whole edge be sharpened.
- Plunge line: the step where the grind starts, next to the ricasso.
Using the names in a project brief
You don't need a finished drawing to start a project, but the brief gets a faster answer when it names the parts. For a folding knife, that usually means:
- Blade length and the thickness at the spine
- Blade shape and grind
- How it opens: flipper, thumb stud, thumb hole or nail nick
- Lock type
- Washers or bearings at the pivot
- Scale material, and liner material if there are liners
- Clip position: tip up or tip down, right, left or both
- Lanyard hole or not
For a fixed blade, swap the middle of that list for the tang type, the guard and the sheath.
Steel is its own decision. We compared the common choices in Knife Steel Types and Hardness Comparison.
If you have a sketch or a reference knife and want to turn it into a spec, send it to us. We make complete knives and also individual components: scales, liners, pivots, clips and fasteners.