Types of Holes
Countersink - is a conical hole cut into a manufactured object, or the cutter used to cut such a hole.
· Allows the head of a countersunk bolt or screw, when placed in the hole, to sit flush with or below the surface of the surrounding material.
Counter bore - makes a flat-bottomed hole that might be used with a hex-headed cap screw
Pilot-Hole - a smaller hole drilled into a material prior to a larger hole being drilled, widening the hole to the desired width.
· Pilot holes are used when driving a screw.
· When a screw is driven into a material, it can act as a wedge, generating outward pressure which can cause many materials to split.
· Drilling a small pilot hole into the material, into which a screw is then driven, less 'wedging' takes place, thereby reducing the likelihood of the material being split.
Through-Hole - refers to a hole that is reamed, drilled, milled etc., completely through the substrate. In other words, a through hole is a hole that goes all the way through something.
Blind-Hole - a hole that is reamed, drilled, or milled to a specified depth, thus without breaking through to the other side of the work piece.
Countersink - is a conical hole cut into a manufactured object, or the cutter used to cut such a hole.
· Allows the head of a countersunk bolt or screw, when placed in the hole, to sit flush with or below the surface of the surrounding material.
Counter bore - makes a flat-bottomed hole that might be used with a hex-headed cap screw
Pilot-Hole - a smaller hole drilled into a material prior to a larger hole being drilled, widening the hole to the desired width.
· Pilot holes are used when driving a screw.
· When a screw is driven into a material, it can act as a wedge, generating outward pressure which can cause many materials to split.
· Drilling a small pilot hole into the material, into which a screw is then driven, less 'wedging' takes place, thereby reducing the likelihood of the material being split.
Through-Hole - refers to a hole that is reamed, drilled, milled etc., completely through the substrate. In other words, a through hole is a hole that goes all the way through something.
Blind-Hole - a hole that is reamed, drilled, or milled to a specified depth, thus without breaking through to the other side of the work piece.