South Bend 9A / 10K metal working lathe 40t Nylon gear (runs quieter and smoother) Specifications: Outer diameter 2.333" (59.2mm) Gear face width .375 (3/8") Center bore .5625 (9/16") with a single 1/8 keyway Diametrical Pitch 18 Part number: 32K40N1 This gear made out of out of Nylon - tough and flexible plastic No lubrication required Only Nylons should be used for gears where a slippery surface is desired. All other materials (PLA, ABC, PET, etc.) will grind creating a plastic dust and eventually fail! For details, please review all pictures and compare to OEM gear shown Do not waste money for ABS, PLA plastic gear that may strip or melt Thank you.