Slang term in the worlds of
hip hop and
DJ culture for
turntables; the source of all proper
beats. The current standard is the
Technics 1200mk2, which was first sold in 1979.
(mkb sez: "1200mk3ds are way better, dood*."... so there you have it.)
Turntables arguably became instruments in their own right with the invention of the mixer and the advent of hip hop, circa 1976** in the Bronx, New York City, USA.
However, the partying ghetto kids of the north borough can look south to Jamaica for the people who influenced their playground-rockin' heroes. Jamaican party DJs as early as the mid-1960s had hacked together crude crossfaders and were pounding back-a-yards with a bass-heavy treat called dub.
Dub parties, and their track-extending DJs, spread to the Caribbean communities of New York City, and thence diffused into the black youth populace as a whole. DJ Kool Herc, a Jamaican immigrant, may have been directly responsible. He is generally credited as the first (non club) DJ to mix one track into another and another and another.
The mixer allowed the DJ to do this; seamlessly segueing one track into another to keep people dancin' for hours. Extended breakbeats gave the hosts of the parties, the Master of Ceremonies a chance to talk up the DJ, himself, and hip hop culture in general. Rhythmically.
Hip hop mythology generally recognizes a DJ named Grand Wizard Theodore with inventing "scratching"; cutting a record back and forth against the needle in interesting rhythms. He claims he stumbled across the technique when his mother barged into his bedroom, yelling for him to turn down the noise. Theodore stopped his record from spinning by lightly laying his fingers on it, but was semi-unconsciously moving his hand back and forth in time with the beats in his head. The resulting sound is legendary.
However, it was Grandmaster Flash who would make it so. Grand Wizard Theodore was Flash's assistant and demonstrated the innovation to him. Flash, himself, is credited with the development of punch phrasing and break spinning, both of which are integral to modern DJing.
"Wheels of steel" should not be confused with the Rolling Stones geriatric rock tour titled "Steel Wheels".
*
mkb continues: "let me actually explain why they are better. 1.) it has a recessed power switch so you don't turn the thing off by accident. 2.) it does NOT have a detent at pitch = 0% so you can make fine adjustments and 3.) it has a button that makes pitch=0% right away."
**
Pinning down exact dates on the creation of the musical aspect of hip hop is nearly impossible. Please don't yell at me.
Thanks to mkb and irexe for corrections and additions. This writeup is also indebted to Nelson George's book Hip Hop America, and http://www.addict.com/issues/5.02/html/hifi/Cover_Story/Turntablism/History_Of/