Abstract: A plurality of bar stock retaining sleeves control the bar stock fed therethrough to a machine center to prevent excessive vibration and end-whipping during a cutting and machining operation. A first retaining sleeve is positioned within the feed orifice of the machine center, and includes a master bushing having an inner diameter substantially equal to the outer diameter of the bar stock being cut, which master bushing is positioned adjacent the orifice outlet at the the cutting head. A second retaining sleeve is supporting exteriorly of the machine center in abutting relationship to the stock inlet of the feed orifice. The second retaining sleeve includes at least two bushings having an inner diameter substantially equal to the outer diameter of the bar stock, the two bushings being connected in spaced relationship to each other by an elongated cylindrical tube having an inner diameter greater than the inner diameter of the connected bushings.