A flat-bottomed cylindrical enlargement of the mouth of a hole, usually of slight depth, as for receiving a cylindrical screw head.
A kind of pin drill with the cutting edge or edges normal to the axis; -- used for enlarging a hole, or for forming a flat-bottomed recess at its mouth.
To form a counterbore in, by boring, turning, or drilling; to enlarge, as a hole, by means of a counterbore.
The act of making one end of a drilled hole larger than the other to permit the head of a bolt or screw to drop below the surface of the workpiece. Counterbores, unlike countersinks, have straight sides (not angled). In woodworking, counterbored holes are often filled with wood plugs or screw but-tons to create the illusion of dowel joinery.
a bit for enlarging the upper part of a hole
a flat-bottomed cylindrical hole at the base of the threads
The larger diameter at the entrance of a drilled hole with a flat bottom. Similar to a countersink except for the bottom configuration.
A concentric diametric enlargement of a hole for part of its depth which forms an angular, radial or flat surface at the bottom.
A parallel-sided depression machined into the mouth of a hole, for instance to hide a screw head.
The process of boring a hole for a screw or bolt so the head is below the wood's surface.
A kind of drill bit which has a pilot which follows a pre-drilled hole to open it up to a bigger size. Will also function as a drive centre. Handy for making lamps.
Cylindrical flat bottomed hole drilled partially through a TSLOTS extrusion piece.
A hole drilled to recess the head of a screw.
Removal of worn rifling at the muzzle by drilling it out larger than the bore diameter to improve accuracy.
The hole in a blind threaded insert which clears the major diameter of the thread in the radial direction and extends axially from the head end of the part to the thread. For inserts with round shanks the counterbore is round. For inserts with hex shanks the counterbore may have a hex shape.
Enlarging the opening of a hole to conceal the head of a bolt, etc.
A tapered recess that allows the head of a screw or bolt to lie below a surface; also to cut such a recess.
A round, flat bottomed depression in an eyelet.
A flat bottomed hole which can be made with a Forstner bit or counterboring bit.
A stopped hole in a workpiece that allows you to set a screwhead below the surface of the wood. You can plug the counterbore to hide the head, shown right.
The increase of the diameter of an opening for only part of the length. Holes though a material may have a one-inch sized diameter of half of the length with only a 3/4 inch diameter for the balance of the hole, making it counterbored to a diameter of one inch to a depth of 1/2 inch.
A counterbore can refer to a cylindrical flat-bottomed hole, which enlarges another hole, or the tool used to create that feature. It is usually used when a bolt or cap head screw is required to sit flush with or below the level of a workpiece's surface (By comparison, a countersink makes a conical hole and is used to seat a flathead screw).