Didnt like having to hold on to the drill...gets alil frustrating when doing more than a few cases so I came up with this.... built from a junk 18v cordless drill. I built the battery pack out of sub c cell batteries tried many dif voltages to get the apeed I wanted and 9.6 was about right then I built a trickle charger so I can always keep the batt. Charging works geat...