Open hole for car shell

C-hing,

May I ask how to make a big hole (approx. 50mm dia.) in the front and rear glass of car shell for ventilation of Engine.
I see many C-hings can make it in perfect circle.
Any special equipment to do it?
Same equipment as the one to make hole for 殼柱?
Thanks!

there has a special pair of scissos are use to cut car shell, the tip of the sessios is a little bit bend , specially for you to cut the circle edge of the shell

你可以買把"圓規刀"

yes, some bookstore will have this 圓規刀

I see! Thanks! All C-hings