Tired of dull drill bits that snap under pressure? Check out Jameco's selection of 0.12 drill bits. Used for a variety of applications like drilling holes in glass PC boards - and available in several sizes including 0.21 inches. Our popular drill bit assortment kit comes with 20-pieces in 7 different sizes. Or take a look at the mini drill bit kit which is excellent for drilling through circuit & proto-boards, and comes with an array of drilling, grinding and sanding attachments.