In this post, we’ll introduce the concept of Countersinks and Counterbores and how these are used in Printed Circuit Boards (of course, countersinks and counterbores are not anything unique to printed circuit boards and are used in a variety of manufacturing of both metal, wood and other materials).

What is a Countersink?

A countersink is a conical hole that is cut in order to allow for a flat head screw to be used.

Why do you need it?

Makes it possible for a flat head screw to sit flush with the surface to make for a very clean look and installation.

What information is required to fabricate a countersink?

Countersinks most commonly will have either an 82 degree or 90 degree angle so a primary consideration is the desired angle. Additionally, you would need to specify the diameter of the smaller hole, and either the maximum diameter or the depth of the countersink. And, whether that hole is to be plated or non-plated. In most cases, these are non-plated but there could be situations where you may be grounding to a chassis and would need to have plating in the hole.


What is a Counterbore?

A counterbore is a cylindrical flat-bottom hole that is cut so that it also allows for a socket cap screw (has a flat head) to be used. The socket cap screw usually has an allen wrench drive (hex) hole.

Why do you need a Counterbore?

It is typically needed for much more secure and stable mountings.

What information is required to fabricate a counterbore?

For a counterbore, you would need to specify the dimensions of the larger hole, the smaller hole and also the depth of the bore. Similar to countersinks, in most cases these will be non-plated mounting holes. In any case, you’ll need to identify the size of the finished hole size.


Not too complex, eh? For some visuals, check out the video below.




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