Countersink & Counterbore

Countersink

A countersink is a cone shaped hole cut into the laminate. It is typically used to allow the tapered head of a screw to sit flush with the top of the laminate. By comparison, a counterbore makes a flat-bottomed hole and its sides are drilled straight down. This is usually used to fit a hex-headed cap or screw.

To accurately drill your countersunk holes, we will need the following information.

• Angle of the drill

• Major Diameter (finished diameter of the hole at the surface)

• Depth the countersink is to be drilled

• On which side of the board is the sink? Top or Bottom?

• The finished diameter of the shaft of the hole

• Is the sink and shaft to be plated or non-plated?

Process capability: The depth tolerance of the countersink hole is +/-0.15mm.

Notice: 1.Countersunk-head screws that follow the ISO standard very often have a 90° angle, if you require the other angle, we need to purchase the drilling tool.

2. The data of countersink hole is mutually restricted, so if you are changing one data, you should change the others accordingly.

Counterbore

A counterbored hole is typically used when a fastener such as a bolt or cap head screw is required to sit flush with or below the level of a surface.

To fabricate your counterbored holes, we need to know the following information.

• Major Diameter (finished diameter of the hole at the surface)

• Depth the countersink is to be drilled

• On which side of the board is the sink? Top or Bottom?

• The finished diameter of the shaft of the hole

• Is the bore and shaft to be plated or non-plated?

• Because the sides of the hole are always parallel, there is no need to specify an angle.

Process capability: The depth tolerance of the step hole is +/-0.15mm.