What Are Countersunk Screws?

What Are Countersunk Screws?
Published: May 1, 2011
Updated: Nov 20, 2021
2 minute read

Use a countersunk screw when you do not want the fixtures to show.

Countersunk Screw

A countersunk screw is a type of fastening that sits flush with the surface of the material it occupies. These screws typically are used so that you can cover them easily with either a screw cap or piece of wood. Other applications include the need for a fastening not to protrude so other objects can rest upon it stably, or to fasten it further to another object. The typical angle of a countersunk screw head is 82 degrees, but this varies depending on the application.

Countersunk Hole

To use a countersunk screw, it is necessary to machine the hole first for it to receive the angle of the screw head easily. Certain tools, such as a cross-hole countersink cutter and a fluted countersink cutter, can bore wood or metal efficiently to prepare a cone seating.

Other Uses

A countersunk screw also can be very useful when dealing with burred holes. Depending on how severe the hole has been burred, it can act as a readily prepared seat for the head of the screw.

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Difference Between a Screw and a Bolt

There actually is no universally accepted distinction between a screw and a bolt. However, a bolt typically will be fastened with a nut that threads onto its end. One major difference is that a bolt almost never has a countersunk head.

The Drip Cap

  • A screw essentially is an item that allows you to fasten or secure one object to another.
  • Depending on how severe the hole has been burred, it can act as a readily prepared seat for the head of the screw.
  • One major difference is that a bolt almost never has a countersunk head.

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William Thomson

William Thomson started writing seven years ago in 2003 and has contributed work to the student newspaper "Uyellnews" and a magazine known as "Words Yes!." William specializes in writing fiction and opinion articles. He graduated from the…

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