Slot milling is a preferred operation for end milling over end milling. A slit or groove may be short or long, closed or open, straight or non-straight，deep or shallow, wide or narrow.

A slotted cutting is used much like a saw to create small grooves and grooves for joinery and biscuits. You can cut grooves on a table saw, but using a slotting knife in a doing planer has certain advantages. For one thing, you'll get the perfect flat cut, which not all saw blades can do. A slotting mill cutter is just a 2-edged end mill for cutting grooves. As the name implies, a larger clearance allows the chip to come out from the back without clogging, and then a groove is cut in the center, which can also be used to cut into a small distance to start cutting in the middle of the material.