Calking Gun Fix-up

This is a caulking gun that was getting thrown away and I did not want to see it go to waste. Tried selling but nobody would buy it since the 12 volt Milwaukee batteries were hard to find. I did not own any 12V batteries so I decided to 3D print and adapter for my DeWalt 20V battery and got the electronics and have an external motor speed control. The usage of WD-40 here is important to keep the rack and pinion gear lubricated and clean. The WD-40 aides in keeping the rack and gear free of adhesive and lubricant because it coats the surface helping to prevent adhesion. Thanks for the opportunity. Long time user- first time caller.