How to upgrade a vintage to modern drill driver

This is a vintage 12V cordless drill driver from Nation, Japan. I'm hard to find its spare part while It has problem with the power switch. The gearbox is still very good, and I want to use this drill with my existing battery (18V6Ah Dewalt). I decided to upgrade it from 12V to 18V by changing the motor, power switch and mount new battery adapter. As the result, It works very well and so powerful. You can see all the process in this video.
I hope you find this video useful and enjoy it!

Battery build guide https://youtu.be/cFZVaCRufMw

Furthermore, I am happy to receive feedback, suggestions to improve myself.
!!! I'm sorry for the mistake if I did in this video !!!
Thank you very much for choosing to watch my video!
Have a nice day
Gear Show

Видео How to upgrade a vintage to modern drill driver канала Gear Show