Drill is a multi-point cutting tool as it contains more than one cutting edges and all cutting edges simultaneously take part in cutting action during machining. Sometime drill is classified as double-point cutting tool because common metal cutting drills contain only two cutting edges; however, drills may contain more than two (3 to 6) cutting edges also (for example, wood cutting twist drills).
What is multi-point cutting tool?
If a cutter contains more than one cutting edge that can simultaneously partake in material removal action during machining, then it is called a multi-point cutter. For example, milling cutter is a multi-point cutter. Except this, reamer, broach, hob, grinding wheel, etc. are also examples of multi-point cutter. On the other hand, a single point cutting tool contains only one main cutting edge that can participate in shearing action. Turning tool, boring tool, shaper, etc. are single point cutter. For further information, you may follow the below links.
- Single point cutting tool – examples, advantages and disadvantages
- Multi-point cutting tool – examples, advantages and disadvantages
- Difference between single point and multi point cutting tools
About drill and drilling operation
Purpose of drilling operation is to originate a cylindrical hole (through or blind). Basically, centering is used for accurately positioning the hole centre, drilling is used to originate the hole, boring is used to enlarge the existing hole, reaming is used to smoothen the hole surface and finally honing is used to super-finish the hole surface (common hole making sequence: Centering –> Drilling –> Boring –> Reaming –> Honing).
Cutting tool used for drilling operation is termed as drill and it usually contains two or more cutting edges. Metal cutting drills commonly have two flutes; whereas, wood cutting drills have more than two cutting edges. Drilling operation can be performed either in dedicated drilling machine (horizontal or vertical type, high productivity), in lathe, in milling machine or using portable hand drills.