Thread: is it illegal to have a larger then 3/8s drill bit on a corded handheld drill?

It is not illegal.

we us a 3/8s or 1/2 inch size corded hand drill, the bit we use is a 3/4 inch size one used for drilling large holes, their is a specially made extension that uses set screws to hold in the bit to the extension that is put in the drill, wondering if this is an OSHA approved mod or illegal?

It's not illegal (assuming the parts are not defective in design or material.)

In any case OSHA requires to follow safety rules when using any power tool, and to READ the tool's manual before using it and it;s accessories.

Illegal???? What have you been smoking? No.