It may be spaced and filed, or it may be knurled, as shown in Fig.
"Scientific American Supplement, No. 312, December 24, 1881" by Various
The knurled retaining screw turned easily; the cup dropped into Brett's hand.
"It Could Be Anything" by John Keith Laumer
You focus the 'scope eyepiece by turning this knurled knob.
"The Flying Stingaree" by Harold Leland Goodwin
Ennis, tensing to spring toward Ruth, saw the two priests at the gray mechanism swiftly turn the knurled black knobs.
"The Door into Infinity" by Edmond Hamilton
Concave knurls are sometimes used for knurling rounded edges on screw heads, etc.
"Turning and Boring" by Franklin D. Jones
Lucifer Furnaces, Inc recently supplied a fifth tempering oven to Accu Trak Tool Corp. A leading manufacturer of precision knurling wheels and holders.
Zak Tool 's Knurled Flat Grip Handcuff Key is available in a desinger pink.
According to the company, the kit is easy to use, and tough with a diamond-knurled grip and all-metal housing.