Countersink

The sink is a drilling method used and the deburring and producing profiled or planner paragraphs in finished holes.

This ensures that the screw heads, nuts or rivets can rest flush with the workpiece surface in the reduction. Lowered holes also facilitate the threading of the better gate.

By type of reduction, there are three methods. Protruding, flat surfaces are created with the Planansenken. By countersinking plan gives an in-depth, plane surface. Profile sinks produces a tapered or otherwise profiled reduction.

Counter sinking

  • Countersinks have a cutting tip shaped like a cone whose apex angle is usually 60 degrees ( for deburring ) or 90 degrees ( Flathead ). Rarely Countersink with 75 ° tip angle ( suitable for Nietkopfsenkungen ) and 120 ° ( suitable for Blechnietsenkungen ). The diameter of the countersunk head wise normal is greater than the shank diameter. To achieve a smooth running when lowering the number of edges is usually odd ( 3 or 5 cutting edges).

A widespread form of countersinks are also the cross- hole countersink which operate in both directions.

  • Counterbore, also called Spot facers, have a straight cutting edge and create a flat reduction ( 180 degrees). You can have two, three or four cutting edges.
  • Facer are an extension of the above -lowering agents represents a journal ( with chamfer ) in the rotationally symmetric axis moves the tool in the bore and enables precise, chatter-free work. The pin can be removed in some embodiments, to facilitate a regrinding of the cutting edges. Facer be used (eg Allen screws ) to produce cuts for screws with cylindrical heads. There are also facing cutters that produce ( like a countersink ) Senkschraubensenkungen (90 degrees or 60 degrees).
  • Core drills are drills with three or four blades. With these ready-made holes to be drilled. They do not belong to the group of countersink.

The reamer for wood turner has the purpose to expand already pre-drilled holes to a specific diameter and simultaneously to smooth the hole walls. The cross section of the tool here is square and the four edges converge in a point.

Countersinks are usually made of high speed steel, but there are also countersink made ​​of hard metal.

4- edged countersink

3- edged countersink

Burr (edge)
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