Knurling

Close-up of a left-right knurl

Pencil sharpener with knurled screw

Knurls or knurled , partly cord , are by means of knurling prepared circumferential shape deviations , which in a metal rotation body are embossed. Knurls can make a workpiece more grippy and thus prevent it from slipping, such as on a dumbbell . The knurling can take various forms and can be introduced either by milling , pressing or by embossing on a lathe .

Coins are knurled to make the grinding or filing of precious metals easier to see on the edge of the coin . The knurling on the edge of the coin often takes the form of a toothing , a leaf edge or a text.

literature

• Raphael Petry: Impressions in: Hartmut Hoffmann , Reimund Neugebauer , Günter Spur : Handbuch Umformen , Hanser, 2012, p. 312 f.