There are three types of countersink drill bit: cylindrical countersink drill bit, cone countersink drill bit and end face countersink drill bit.

Column countersink drill bit is used to spot face cylindrical countersink. The main cutting function of cylindrical countersink drill bit is the end blade, and the bevel angle of spiral groove is its front angle. There is a guide post at the front end of the countersink drill bit, and the diameter of the guide post is closely matched with the existing holes of the work pieces to ensure good centering and guidance. This kind of guide post can be made to be detachable or integral.

Cone countersink drill bit is used for spot facing cone countersink. The taper angle of cone countersink drill bit is different according to the requirements of cone countersink of workpiece, generally, there are four kinds: 60 °, 75 °, 90 ° and 120 °. 90 ° are most common.

End face countersink drill bit is specially used for face spot facing . The end face countersink drill bit can ensure the perpendicularity between the end face and the hole center line. When the hole diameter is small, in order to maintain a certain strength of the tool bar, a section of the diameter of the tool bar head can be matched with the machined hole as a gap of to ensure a good guiding performance.
#pilot #hole #and #countersink
https://www.betalentcarbide.com/products/countersink-drill-bit.html