ATLAS CRAFTSMAN 10 12" Lathe slow feed half speed Nylon Gear This fine Nylon gear has improved design for better durability and performance It is superior to other plastics 3D printed replacements Nylon is a first choice gear material - it won't create plastic dust as ABC does! 3D printed out of Nylon - tough and flexible plastic Nylon naturally slippery, no lubrication required! Runs quieter and smoother Only Nylons should be used for gears where a slippery surface is desired. All other materials (PLA, ABS, PET, etc.) will grind creating a plastic dust and eventually fail! For details, please review all pictures May fit other 1/2" bore lathes as well. 24t gear outer diameter: 1.625" 48t gear outer diameter: 3.125" Gear face width: "0.5" (24t gear) + 0.5" (48t gear) = 1" Overall Center bore: 1/2" (0.5") DP: 16 Do not waste your money on ABS or PLA plastic gear that may strip or even melt! Introductory price - please share installed images and review. This compound gear will reduce the normal feed rate .0042" per revolution by 1/2 factor to .0021". Slow feed produce better finishes using power carriage. Without the gear, the first 2 lines of the QC Gearbox are: A-IN 4,4.5,5,5.5,5.75,6,6.5,7,7.5 A-OUT 8,9,10,11,11.5,12,13,14,15 With the gear is installed double the numbers on QC gearbox to get the following TPI's for threading: A-IN 8,9,10,11,11.5,12,13,14,15 A-OUT 16,18,20,22,23,24,26,28,30. With 12 inch Craftsman / Atlas lathe shown on the last image. The compound 48 / 24 gear in place, you lose the "slide" capability. There is no "A-IN" position so you lose not just the top row of threads but the top two rows. The largest thread you can cut without moving anything around is 16 t.p.i.