A counterbore is typically a cylinder shaped flat-bottom hole which lets the screw head or bolt with a flat underside to rest firmly or that makes another small coaxial hole enlarge. A counterbore hole is usually put for usage when a fastener, such as a hex head or socket head cap screw, is needed to sit flush with or below the workpiece’s surface level as opposed to a countersink which is about making large conical shape. Thus, a counterbore is also known for its ability to create a perpendicular surface for a fastener head on a non-perpendicular surface. In simple words, the function counterboring is a means of setting a fastener below the surface of the workpiece and made with standard dimensions for a certain size of screw or are produced in sizes that are not related to any particular screw size.
A countersink forms a conical hole cut into a produced object correspond to the angled shape on the base of a flat-head screw or use the cutter to cut such outlet. A common use is to allow the tapered head of a countersunk bolt or screw, when positioned in the hole, so that it sit flush with or beneath the surrounding material’s surface or the top of the laminate generally used to fit a hex-headed cap or screw. A countersink may also be beneficial to eradicate the burr left from a drilling or tapping process thus recovering the product’s finishing and get rid of any perilous sharp edges.