Helix angle the helix angle. The efficiency can be plotted versus the helix angle for a constant friction, as shown in the adjacent diagram. The maximum efficiency is a helix angle between 40 and 45 degrees, however a reasonable efficiency is achieved above 15°. Due to difficulties in forming the thread, helix angle greater than 30° are rarely used. Moreover, above 30° the friction angle becomes smaller than the helix angle and the nut is no longer self-locking and the mechanical advantage disappears. In helical and worm gears, the helix angle denotes the standard pitch circle unless otherwise specified. Application of the
360 Degrees of Billy Paul was similarly enthusiastic in discussing how Paul's sound developed over the years from the early club jazz of "Feelin' Good at the Cadillac Club" (1968) to the merging of jazz and soul on "Going East" (1971): "and then we did Billy's "360 Degrees" album and it all came together with "Me & Mrs. Jones." During his appearance on "Soul Train" in October 1972, Paul was asked by host Don Cornelius whether he had a jazz background. Paul used the opportunity to promote his new album and highlight its diverse styles: “That's very correct. I've been singing since I was 11.