Boring Tool is a Single Point Cutting Tool or Multi Point Cutting Tool?

Boring tool is a single point cutting tool. As depicted below, a boring tool consists of only one main cutting edge, similar to single point turning tool (SPTT). However, large diameter rough boring tools with multiple cutting edges are now-a-days available in the market.

Boring bar
Boring tool with indexable inserts and internal coolant supply facility. (Image source www.walter-tools.com)

What is single point cutting tool?

A single point cutting tool contains only one main cutting edge that can perform material removal action at a time in a single pass during machining. Turning tool, used for turning operation on lathe, is the common example of single point cutter. Shaping tool, planing tool, slotting tool, and boring tool are also single point cutting tools. On the other hand, a multi-point cutting tool contains more than one main cutting edge that can simultaneously partake in material removal action during machining. Examples include milling cutter, reamer, broach, grinding wheel, etc. For detail information, you may read following articles.

About boring tool

Boring is one machining process by which existing holes (either pre-drilled or cast) can be enlarged. Basically, drilling is used to originate a hole, boring is used to enlarge the hole (to increase diameter of hole) and reaming is used to smoothen the surface of hole (common hole making sequence: Centering –> Drilling –> Boring –> Reaming –> Honing). Boring operation employs a single point cutting tool, called boring tool. Because of similarity with external turning, boring is frequently termed as internal turning operation. The operation can be performed either in dedicated boring machine (provides high precision, can be horizontal or vertical), in milling machine or in lathe. It is usually performed to accomplish the following tasks.

  • To enlarge the diameter of pre-drilled or cast holes.
  • To improve accuracy and tolerance in dimension of hole.
  • To convert a straight hole into tapered one.