TYPES OF COUNTERSINKS AND THEIR APPLICATIONS

Various types of countersinks are available, differing both in their shape and in the way they are used. What they have in common is that they are used to machine a hole that has already been drilled. The countersink itself therefore does not drill the hole; it only subsequently cleans or countersinks it.

Countersinks are used primarily for deburring (cleaning up) a drilled hole or for countersinking the hole so that space is created for recessing the screw head.

THE MAIN TYPES OF COUNTERSINKS INCLUDE:

• Conical countersinks
• Countersinks with a cross-hole
• Slip-on countersinks (mounted directly on the drill bit)

CONICAL COUNTERSINK

As the name suggests, the head of this countersink has the shape of a cone.

The head consists of an odd number of cutting edges. Usually 3 or 5. The chips produced are removed through the grooves between the cutting edges.

When choosing a conical countersink, it is necessary to know what work it will be used for and, accordingly, to choose the type with the correct countersinking angle.

There are different countersinking angles, each intended for a different type of work:

• 60° for deburring
• 75° for rivet heads
• 82° for countersunk screws – US standard
• 90° for countersunk screws
• 120° for countersinking rivets into sheet metal
• 180° for screws with cylindrical and hexagonal heads

In our range you will find both of the most common types:

• 60° for deburring
• 90° for countersinking for a countersunk screw head, also usable for deburring

Depending on the material being machined, it is then possible to choose the variant:

• HSS (high-speed steel)
• HSS-Co. (cobalt-alloyed high-speed steel)

COUNTERSINK WITH A CROSS-HOLE

These countersinks are equipped with a hole that forms an angle of approx. 45° with the countersinking axis, creating 2 cutting edges.

The chip produced is removed through this hole, which prevents the chip from getting stuck between the tool and the material being machined, as well as preventing the tool from getting stuck in the material. The countersinking angle can again be 90° or 60°.

This tool is very simple and clean to work with. It can be used both for deburring and for countersinking a hole for a screw head.

SLIP-ON COUNTERSINK

This countersink is used exclusively when recessing screws into wood and is mounted directly on a twist drill bit.

Drilling the hole and countersinking it is therefore practically carried out in one working step.

Recommendations for working with countersinks

When countersinking, it is important not to apply too much pressure to the tool and to work at the correct speed. Especially with hard materials, very low speeds should be selected.

The more slowly you work with the countersink, the smoother the work will be and the less the countersink will heat up. This will also extend the service life of the tool.

The countersinking depth may vary depending on the type of work you are carrying out with the countersink.

For deburring, it is only a few millimetres; when recessing screws, countersinking can be carried out up to the point where the maximum diameter of the tool reaches the level of the material surface.