An expandable drill bit for use with earth drilling equipment. The material can be used as a bio-material. A first end of the arc-shaped feeding portion is connected with the radiator, and a second end of the arc-shaped feeding portion is connected with the grounding portion. The cartridge loading device has a front end at which cartridges are inserted into the opening, a rear end and opposite sides extending between the front and rear ends. The slide assembly is hingedly mounted onto the base assembly by at least one hinge.