From Blog
An ode to knurling
An appreciation of knurling — the obscure, unglamorous craft that decides whether a bar actually grips.
Published
by Adarsh Gopal
This appreciation post is for an obscure part of gym equipment: knurling.
Knurl, for those not in the know, is a cross-cross pattern on portions of gym equipment that you hold. That’s not too complicated now is it? To that I say ‘Hold my bar’.
Knurling is painstakingly applied on a bar by a lathe operator (larger manufacturers now use CNC machines to lay down knurling). The longer the surface, the more precision it takes to ensure the knurl runs continuously and smoothly along the length of the bar. One small miss and a bar might be scrapped if the knurling is not continuous or inconsistent. You will find knurling on dumbbells, barbells, dip bars, pull ups bars, centre mass bells and practically any object that requires the user to hold it and move in tandem with the object.
Things are knurled for one obvious reason. A bare metal surface: coated, painted or bare, will be slippery to hold. That is not good if you plan to grip or hold an object with any reasonable load comfortably.
Knurl comes in different depths and sharpness. A sharp knurl offers better grip but can be painful to hold for longer periods. A blunted knurl makes it more comfortable to hold but the grip is less grippy (DUH). On quality equipment, you will usually encounter something right down the middle.
Lest you wonder if it’s a single nut who is fixating on knurling in a LinkedIn post, every single barbell manafacturer of note has a signature knurl on their bar that varies based on when and where and for what the bar is used. Eleiko, the maker of barbells used in the Olympics, even knurls small knobs and adjustment levers on their equipment for a distinctive look.