What is Knurling?

In manufacturing, knurling is a finishing process used to create any combination of horizontal, vertical or crossing lines on the surface of a fitting.

Overview of Knurling

Even if you’re unfamiliar with knurling, you’ve probably seen a knurled product or object before. Hammers, wrenches and other hand tools are often manufactured with a knurled grip. When performed on the grip, knurling creates a patterned texture to prevent hand slippage. Knurling doesn’t add material to the grip. Rather, it creates the textured surface either through pressure or by cutting away some of the material.

What is Knurling? example of machine tectuing

Hand vs Machine Knurling

There are two primary ways to perform knurling: by hand or by machine. The former involves the use of a rolling roll that creates the desired pattern as it’s pressed against the surface of the workpiece, whereas the latter involves the use of a lathe to cut the desired pattern into the workpiece.

Hand knurling is the most basic method, requiring nothing more than small roller tool. As the worker runs this tool across the surface of a workpiece, it leaves behind a textured surface in the pattern of the tool’s indention. Machine knurling, on the other hand, is a more complex process that requires a lathe. Unlike hand knurling, machine knurling doesn’t create textured surfaces through pressure. Instead, it uses a bit to cut the material out of the workpiece.

Knurling example on light fixture with textured socket
Buster + Punch

I was first introduced to knurling in 2013 when I attended the London Design Festival with Modenus and saw the Buster + Punch booth. I can’t tell you how disappointed I was when I learned their gorgeous fixtures weren’t compatible with US voltage.

Buster + Punch founder, Architect and industrial designer Massimo Buster Minale, has a reputation for crafting precision-cut lighting and hardware inspired by motorcycles and London’s subculture scenes. Minale used his passion for making custom motorbike handles as inspiration for his hardware. Using the knurling technique also signified his use of quality materials – only solid metal can be successfully knurled.

Knurling example on light fixture with textured faucet handle
Luxury faucet manufacturer Franz Viegener recently introduced new tactile and faceted handle options for their Nerea and Lollipop collections.

Customization is the name of the game in today’s competitive design market. It appears years of click-to-buy sameness has resulted in a bit of fatigue, prompting more buyers to want handmade, customizable items.

What is Knurling, example on door handle
Emtek Select Collection let’s you choose your textured lever grip, stem design, backplate and finish options

Knurling can enhance the aesthetics of a product by introducing an attractive pattern to its surface. Most people will agree that textured finishes are more attractive than smooth finishes. Aside from aesthetics, though,  knurling can improve their performance and usability of items such as handles that need gripping.

Knurled handle on kitchen range with brass accents
JennAir limited edition range with hand-applied, distressed finish. and knurled handles was first unveiled in 2018

While some design experts posit Industrial Design themed interiors will be out in the new decade I believe texture is in. Not all knurled fittings and fixtures fall into the industrial category. So, it you like the new Grandmillenial style and want to mix in a few well-made items with knurled texture I say go for it.

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