Boring Machines Information

Boring machineBoring machines cut the inside of a bore to enlarge its diameter. Boring machines are developed to make a bore in the shortest time and produce the highest possible surface finish and tolerances. There are many 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


A line boring machine bores holes in heavy construction equipment, such as cranes and endloaders, 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 highly rigid construction. A directional boring machine includes a frame and a drive mechanism that is slideable 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 work pieces. 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.


There are several ways in which boring machines function. A line boring machine is capable of measuring bores using calibrated internal and external micrometers and its size ranges from 50 mm to 2000 mm in diameter. A tunnel boring machine consists of one or two shields and trailing support mechanisms. Some of the specifications of a horizontal boring machine include a boring spindle diameter of 100 mm, maximum torque on the spindle of 1100 Nm, and the range of spindle speed of 10–1100 RPM. A cylinder boring machine has a boring diameter of 65-140 mm and a spindle speed of 250 r/min and 380 r/min. A jig boring machine maintains high accuracy between multiple holes, and the tolerance is ±.005 mm. Some specifications of a vertical boring machine include a maximum drilling stroke of 2 in., supply voltage of 220 V, and spindle rotation of 3300 RPM. Boring machines are designed and manufactured to meet most industry specifications.

Boring machines are used in many applications. Examples include pile top drilling, doweling, and concentric reboring of holes on dozers, backhoes, and endloaders. Boring machines adhere to International Standards Organization (ISO) standards.

Related Information

CR4 Community—Micro Hole Boring

Engineering360—Tunnel Boring Machines Information

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