counterbore

A spotface often takes the form of a very shallow counterbore.

The counterbore is often covered with a dust cover.

The uppermost counterbore tools shown in the image are the same device.

It was found that inserting a counterbore here reduced wetting.

Another type of useful drill bit that can be used with all electric drills is a counterbore bit.

A tool referred to as a counterbore is typically used to cut the spot face, although an endmill may also be used.

The lower counterbore is designed to fit into a drill chuck, and being smaller, is economical to make as one piece.

A counterbore is also used to create a perpendicular surface for a fastener head on a non-perpendicular surface.

The cutters most often used to cut spotfaces are counterbore cutters and endmills.

The smaller top item is an insert, the middle shows another three-fluted counterbore insert, assembled in the holder.

The head of the bolt or the nut sits inside a counterbore that is also threaded to accept a crank puller tool.

(By comparison, a counterbore makes a flat-bottomed hole that might be used with a hex-headed capscrew.)

The transition between this ground diameter and the original diameter is either straight, to form a counterbore, or angled, to form a countersink.

As mentioned above, the cutters that produce counterbores are often also called counterbores; sometimes, to avoid ambiguity, the term counterbore cutter is used instead.

Zero-angle cutters obviate this, functioning similarly to the traditional counterbore cutters of manual machining but needing no pilot.

A counterbore (symbol: ⌴) is a cylindrical flat-bottomed hole that enlarges another coaxial hole, or the tool used to create that feature.

Whereas a counterbore is a flat-bottomed enlargement of a smaller coaxial hole, a countersink is a conical enlargement of such.

The dustcap serves to protect the threads (on the inside of the counterbore), which are used with a crankarm puller to remove the crankarm from the spindle.

The safety recommendation relates to a possible manufacturing issue with a misaligned counterbore in some pressured oil pipes, which could lead to fatigue cracking, oil leakage, oil fire, and engine failure.

Others point to the problems with the four owner selected main propulsion engines that plagued the Skeena Queen following commission, including excessively high noise levels and cylinder counterbore cracking in the high-speed engines.

In either case, the tip of the counterbore has a reduced diameter section referred to as the pilot, a feature essential to assuring concentricity between the counterbore and the hole being counterbored.

It is usually a piece of metal or plastic that, on the crankarm, is snapped or screwed into the threaded counterbore, which houses the bolt that holds the crankarm to its axle, the bottom bracket spindle.