Countersinking Guidelines

Countersinking is a vital process in sheet metal fabrication, particularly when creating components that require a smooth surface with no protruding screw heads or fasteners. This technique involves enlarging the top portion of a pre-drilled hole, creating a tapered seat that allows flat-head screws or bolts to sit flush with or beneath the surface of the sheet metal.

Countersink Sizes

Fabworks gives you the ability to upload STEP files with your countersinks pre-drawn. This reduces the amount of time you will spend configuring your order. When taking this approach, you can pick from any diameter of countersink as long as it's one of the following angles: 82°, 90°, 100°, or 120°.

Please keep in mind that we hold a tolerance of -.000"/+.015" on all countersinks, which ensures that your bolts will sit sub flush with the surface of the sheet metal. When powder coating your parts, we recommend accounting for the ~.004" of added thickness if a sub flush fit is critical.

Configurable Countersinks

In some cases you might want to add a countersink to a preexisting model. You can use our hole operations tool to add one of the following countersinks to your parts.