This belt gear/pulley kit will replace existing belts and gears... especially those that use obsolete OEM belt. ** Small gear does not have a keyway ** fits Cummins, Speedway Series CT0618-300 / CJ0618-200 12" / 8" **Grizzly 8690 uses 15mm bore large gear...please let me know if this is your model** **SIEG C2 C3 ** you will need to modify for this to work 5278 Cummins 7x12 Mini Lathe 82500 Micro-Mark 7x12 Mini Lathe 82710 Micro-Mark 7x14 Mini Lathe G8688 Grizzly 7x12 Mini Lathe Grizzly G8690 ..and other units ..see below. Fits Asian Mini Lathe 7" x 10",12", 14","Pulley/Belt Reduction Power UpGrade, Aluminum XL Pulleys Belt, Approx 3 to 1 Reduction instead of the OEM 1.82 to 1, 40% Power increase, Ideal for spinning those 4 5 Inch Chucks, ? **This upgrade lowers Max RPM in Low Gear to Approx. 700 RPM, and 1600 RPM in High Gear.** **Please read below to make sure this will work on your shaft.** **This Upgrade Kit fits machines with (small gear) 8mm motor shaft bore w/3mm Key, (large gear) 10mm motor shaft bore w/ 4mm Key, ***IF YOU NEED THE LARGE GEAR TO HAVE 15MM BORE w/ 4mm Key **LET ME KNOW** otherwise we will send the 8mm bore on both.*** Comes with (2) 4mm set screws on the hub of each Gear/Pulley Note: This is an XL Pulley/Belt System,INDIVIDUAL COMPONENTS WILL NOT INTERCHANGE WITH THE OEM BELT/PULLEY SET-UP THE MINI LATHE COMES WITH STANDARD, XL is .200" pitch and the OEM belt is labeled 1.5 x 70, !!there is no such thing!!, the actual belt pitch is .1875" and is not an Industrial Standard Manufactured Timing Belt. ATTENTION: ? we stock belts for power tools, lawn mowers, tractors and farm equipment, vintage electronics A/V, marine auto pilots, scooters, Gilmer drives, Aircraft seats home appliances, vacuum cleaners, sewing machines, RC R/C remote control cars, planes, boats and helicopters ..and many more hard to find and OBSOLETE belts. Do you have an old belt no longer made? We can make it for you! Custom made belts available upon request.