Countersinks and Counterbores
This is a continuation of our PCB-101 series. In this post we will talk about Countersinks and Counterbores.
First I will highlight what these are and then what we need to know when manufacturing a printed circuit board that needs to have countersinks and counterbores.
Countersinks and counterbores are not anything unique to printed circuit boards, by the way. They are used in a variety of manufacturing of both metal, wood and other materials.
I also want to thank Dingo from our fabrication department. Dingo has been working in pcb manufacturing since 1966 and been with Bay Area Circuits since its inception more than 37 years ago. He took me to school (maybe a little old school even) on countersinks and counterbores.
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 do we need to know to manufacture countersinks?
Countersinks most commonly will have either an 82 degree or 90 degree angle. We just need to know what you want.
Of course we need to know the diameter of the smaller hole. We also need to know if the hole is to be plated or not. In most cases these are not plated but there could be situations where you may be grounding to a chassis or something and would need to have plating in the hole.
What is a Counterbore?
A counterbore is a cylindrical flat-bottom hole that is cut that 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 do we need to know to manufacture counterbores?
For a counterbores we need to know the dimensions of the smaller hole and the dimension of the larger hole as well as the depth of the bore.
Again in most cases these will be unplated mounting holes but in some cases you may require plating. We just need to know what you want the finished hole size to be.
Ok there you have it, the basics of countersinks and counterbores for printed circuit board manufacturing.
If you have any questions comments or examples of how you have used them please post in the comments below.
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