92Pcs Plastic DIY Four-wheel Drive Robot Kit Gear Motor Rack Pulley Gearbox Module Toy Auto Handmade Spare Parts

92Pcs Single / Double Plastic Gear Motor Rack Pulley Gearbox Model Toy Car Auto Craft DIY Accessories Four-wheel Drive Robot Kit Product Introduction: 1.Modulus:0.5M 2.Hole Diameter:0.8,1,1.9,2.05,2.55,3 3.Material:POM plastic >> DIY knowledge guide (1) gear diameter calculation formula: gear outer diameter (tooth top circle) = (number of teeth +2) * modulus (2) If it is 2mm axis, with tight gear, please choose 1.9mm hole gear; With the loose gear, that is free to slide, please select the 2.05mm hole gear; In other words, tightly selected with a small 0.1mm hole gear, loose with a large selection of 0.05mm gear