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Considerations when adding countersinks on sheet metal parts


On occasion, it may be necessary to add conical holes, known as countersinks, to your sheet metal parts.

When it comes to countersinks, there are three essential measurements to consider: major (diameter at the top of the opening, where the screw head will sit), minor (the smaller diameter at the bottom of the opening), and angle (the angle of the screw or rivet head). It's worth noting that the standard angles used in countersink designs vary depending on the country and the type of hardware available.

There are two primary methods for adding countersinks to a part:

One way is to use a CNC punch press or turret press to create formed countersinks. No manual machining is required. First, a hole is punched through the material, resulting in a slightly larger minor measurement. Then, a die that has the same angle as the screw is punched through. This causes the material to move, reducing the diameter of the minor to achieve the correct size. Finally, the screw is inserted.

Another way is through machining, which involves using a drill press or end mill. To create the countersink, a drill or a laser is used to cut a hole through the material that matches the desired minor dimension. Next, a drill bit is used to form the conical shape needed for the hardware to fit. This method is best suited for prototyping or small volume orders.

Choosing the right hardware for your project is a critical step since the hardware type and material will dictate the tooling, the angles, and measurements. It's also important to check that there won't be any interference between the fastener and the mating part. Keep in mind the material thickness, and consider a wider angle for thin materials and undercut hardware for added security.
    Moravce, Gorenjska - si

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