Design Atlas
한국어
⚙ Product & industrial design

Knurling

널링(요철 가공)

A repeating pattern of small ridges — usually diamond-shaped or straight — cut into a surface that gets gripped or turned by hand, to reduce slipping.

Also known as: Knurl pattern다이아몬드 널링가공 요철
···
html
<div class="knu-cap">diamond knurl — grip texture</div>
css
.knu-cap{position:absolute;left:0;right:0;bottom:6%;text-align:center;font-size:clamp(9px,2.4vmin,13px);color:#f1f0eccc}
js
import * as THREE from 'three';
const renderer = new THREE.WebGLRenderer({ antialias: true });
renderer.setPixelRatio(Math.min(devicePixelRatio, 2));
document.body.appendChild(renderer.domElement);
const scene = new THREE.Scene();
scene.background = new THREE.Color(0x0d0d12);
const camera = new THREE.PerspectiveCamera(38, 1, 0.1, 100);
camera.position.set(0, 0.3, 6.4);
const canvas = document.createElement('canvas');
canvas.width = 256; canvas.height = 256;
const ctx = canvas.getContext('2d');
ctx.fillStyle = '#b9bec4'; ctx.fillRect(0, 0, 256, 256);
ctx.strokeStyle = '#6b6b76'; ctx.lineWidth = 3;
for (let i = -256; i < 512; i += 22) {
  ctx.beginPath(); ctx.moveTo(i, 0); ctx.lineTo(i + 256, 256); ctx.stroke();
  ctx.beginPath(); ctx.moveTo(i, 256); ctx.lineTo(i + 256, 0); ctx.stroke();
}
const tex = new THREE.CanvasTexture(canvas);
tex.wrapS = tex.wrapT = THREE.RepeatWrapping;
tex.repeat.set(3, 1.4);
const geo = new THREE.CylinderGeometry(1.05, 1.05, 2.3, 48);
const mat = new THREE.MeshStandardMaterial({ map: tex, roughness: 0.55, metalness: 0.5 });
const knob = new THREE.Mesh(geo, mat);
scene.add(knob);
const key = new THREE.DirectionalLight(0xffffff, 2.2); key.position.set(3, 4, 5); scene.add(key);
const rim = new THREE.DirectionalLight(0x8fb0ff, 0.7); rim.position.set(-4, -1, -3); scene.add(rim);
scene.add(new THREE.AmbientLight(0xffffff, 0.4));
function resize() { renderer.setSize(innerWidth, innerHeight); camera.aspect = innerWidth / innerHeight; camera.updateProjectionMatrix(); }
addEventListener('resize', resize); resize();
renderer.setAnimationLoop((t) => {
  knob.rotation.y = t * 0.00045;
  camera.lookAt(0, 0, 0);
  renderer.render(scene, camera);
});

Knurling started as a metal lathe technique — two knurl rollers with a pattern cut into them press against a spinning workpiece and displace (not cut away) material outward, raising a grid or diamond pattern. A smooth cylinder gets slippery the moment a hand has water or oil on it; ridges give the skin something to catch on, raising friction. It's why a camera lens's aperture ring, a pen's grip section, and a tool's handle are almost always knurled.

The pattern depends on the job. Straight knurling resists sliding along the axis; diamond knurling resists in both directions (push and twist), which is why it shows up so often on dials and knobs meant to rotate. Ridges spaced too tightly scratch the skin more than they help grip; too widely spaced and the grip feels flat — so the spacing is usually settled by hand, comparing several physical prototypes rather than by calculation alone.

On injection-molded plastic parts, the pattern is machined into the mold surface itself and stamped into every part; besides increasing surface area to resist slipping, it also reads visually as "precision-machined," borrowing a cue normally associated with metal parts.

When to use

When designing a dial, knob, or grip that gets turned or held by hand — especially one that might be operated wet or gloved.