Finding the G Ratio
The G ratio is the formula to determine the ability of a grinding wheel to remove stock from a work piece. A wheel that can grind efficiently on an easy to grind material with minimal wheel wear will have a high G ratio. The G ratio is the total volume of material removed from the workpiece divided by the total amount of wheel wear. The formula for the G ratio is as follows:
G = Vw/Vs
Vw is the volume of material removed from the work piece. Vs is the Volume of total wheel wear. Both figures are take in terms of cubic inches. From that you can see that if the wheel removes a large amount of material with little wheel wear the G ratio will be high. If the wheel is soft and does not remove a lot of material but the wheel wear is high, the wheel will have a G ratio that is low.