Countersunk holes in a PCB: countersink and counterbore, made on request
A countersunk hole has a conical or stepped recess so that a screw head sits flush. We can make them on request, and decide each case with you.
Countersink and counterbore
A countersink is a hole with a conical widening on one side of the board, so that a flat-head screw sits flush with the surface. A counterbore is a hole with a flat-bottomed step, for the head of a cap screw or a bolt. Both are mechanical features: they are used to fasten the board and they carry no signal.
Not the same as castellated holes
Castellated holes are plated holes cut in half at the board edge, so that a module can be soldered onto another board (castellated holes). A countersunk hole is a hole inside the board with a recess for a screw head. They are different features with different purposes.
What we can make
We can make countersunk and counterbored holes, but only on request. We have no fixed specification for them: whether a given hole can be made, and how, depends on the board thickness, the diameters and the depth, so we decide each case together with you before the order.
What to send us
A drawing or a note with:
- the diameter of the hole and the diameter of the recess;
- for a countersink, the angle of the cone; for a counterbore, the depth of the step;
- the side of the board where the recess is;
- whether the hole is plated or not;
- the board thickness you plan to use (standard PCB thickness).
Remember that the recess removes material: keep copper and components away from it, and check how much board thickness is left (cavities are limited in the same way).
How to ask
Write the countersunk hole in the notes of the request, as one of the special features (what to put in a request), or contact us with your drawing before you order. We answer whether it can be made and under which conditions. For standard holes see vias and hole sizes.
Frequently asked questions
Do you make countersunk holes?
Yes, on request. We decide each case with you, because we have no fixed specification for them.
What is the difference between countersink and counterbore?
A countersink has a conical recess for a flat-head screw; a counterbore has a flat-bottomed step for a cap screw or a bolt head.
Are countersunk holes the same as castellated holes?
No. Castellated holes are plated holes cut in half at the board edge for soldering a module; countersunk holes are screw holes with a recess.
What do you need to quote a countersunk hole?
The hole and recess diameters, the angle or the depth, the side of the board, whether it is plated and the board thickness.
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