Boring Machine: Definition, Types, and Application

What is a Boring Machine?

A carpenter’s boring machine is a hand-driven machine to bore holes in beams such as in the process of making a mortise or making holes for the wooden pegs which hold mortise and tenon joints together.

Boring machine, device for producing smooth and accurate holes in a workpiece by enlarging existing holes with a bore, which may bear a single cutting tip of steel, cemented carbide, or diamond, or maybe a small grinding wheel.

Single-point tools, gripped in a boring head attached to a rotating spindle, are moved circularly against the sides of the existing holes. The diameter of the hole swept out by the tool is controlled by the adjustment of the boring head.

Grinding-wheel cutters have a planetary motion, rotating rapidly about their own axes, which in turn slowly rotate with the boring head about the spindle axis; the hole diameter is controlled by adjusting the distance between the wheel axis and the spindle axis. The spindles on boring machines may rotate

Boring machines used in toolmaking shops have one vertical spindle and a work-holding table that can be moved horizontally in two directions perpendicular to each other so that holes can be accurately spaced. On some machines, the spacing error is less than 0.002 percent. In mass-production plants, special boring machines with multiple spindles are common.

History

Before boring machines were invented, carpenters used hand-powered augers to boreholes. Most common were T-handled augers. The shape of the drill bits changed over time, with the spoon bit and shell bit being common before the invention of the spiral or twist bit in 1771 which removes the cuttings as it turns.

The exact origin of this invention is not known, but the earliest patent is in the United States in 1830 by J. Beckwith and was as tall as a man and operated by a large wheel from the side.

Boring machines use twist auger bits usually ranging in size from 7⁄8 inch to 2 inches. The machines hold the bit perpendicular (square) to the face of the timber and are operated with both hands while the operator sits on the base to keep the machine from moving. Some machines can be set at an angle.

Boring Machine

Types of Boring machines

Examples include:

  • Line boring machines
  • Tunnel boring machines
  • Horizontal boring machines
  • Directional boring machines
  • Cylinder boring machines
  • Jig boring machines
  • Portable boring machines
  • Vertical boring machines
  • Coupling boring machines

Applications of Boring Machine

A line boring machine bores holes in heavy construction equipment, such as cranes and end loaders, and is a very economical piece of equipment. A tunnel boring machine is capable of drilling a bore in everything from hard rock to sand and produces a smooth tunnel wall.

A horizontal boring machine is a time-saving machine used to bore holes in a highly rigid construction. A directional boring machine includes a frame and a drive mechanism that is slide-able and is mounted on the frame.

A cylinder boring machine is mainly used for reboring engine cylinders in automobiles. A jig boring machine is used to accurately enlarge existing holes and make their diameters highly accurate. They perform operations such as drilling, boring, and counter-sinking holes in metal workpieces.

A portable boring machine is a flexible, powerful, and easy-to-use machine that is available with a pneumatic or hydraulic drive. A vertical boring machine is designed for manual vertical drilling and it has a drill chuck. A coupling boring machine is designed to bore precision couplings. Other boring machines are commonly available.