This is a 4 to 1 gear reduction with strong metal gears. Large gear has 60 teeth and small has 15 teeth. We use this for our rack and pinion model Plasma CNC. This will give you 4 times more power so you will have enough power to do milling and more accelerations to come out of corners quicker to get a more even cut when plasma cutting. You can use these instead of belt drive and never replace a belt again. Easily drill I.D. to what you need.