6'' 3-Jaw Self-Centering Lathe Chuck The 6'' 3-jaw lathe chuck is made of high-strength HT300 material with strong compression resistance and long service life. It features an internal and external jaw to clamp larger-sized industrial components and a self-centering function to avoid repeated calibration. Superior HT300 Material High Precision Internal & External Jaw Simple & Easy Operation 6'' 3-Jaw Self-Centering Lathe Chuck The 6'' 3-jaw lathe chuck is made of high-strength HT300 material with strong compression resistance and long service life. It features an internal and external jaw to clamp larger-sized industrial components and a self-centering function to avoid repeated calibration. Key Features Superior HT300 Material: Our 3-jaw lathe chuck is constructed from HT300 material, 20Cr steel chuck jaw with 53HRC hardness, and 40Cr steel scroll with 45HRC hardness. The lathe chuck is quenching hardened for superior hardness and rust resistance, providing outstanding working