I think there are some air vent at the back of blade and at the end where we hold the grinding machine If we make a mistake motor will definitely burnout and an electric shock will surprise us.

That trick where you remove the nail while placing a piece of wood underneath the hammer also works well to not leave hammer marks on the wood.My first trick would be to show a nailing hammer using the side for more survace than the normal or the pointy end, slightly to the heavier side in the middle of the mass.

That way even “left handed” apperentices can get use to some skills with that tool.You are my teacher! Out of 48 channels in this field, I chose you. Good luck with all your work. I try to be as similar to you as possible. How to contact you teacher !!!