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The line boring machine. Applications, capabilities and features


What are line boring machines and how are they used? Read on to find out more and watch the video to see them in action.

The basics: what is a line boring machine?

A line boring machine is used for enlarging a hole that has already been drilled or cast, using one or more cutting tools held within a boring head. In doing so, the operation achieves greater accuracy of the hole diameter.

Common Applications


Line boring machines are used on a wide range of projects, with some common examples  including:

  • Excavator buckets
  • Transfer gearbox housings
  • Stern tubes and rudder bores in the shipbuilding industry
  • Drive shaft housing boring
  • A-frame supports
  • Hinge pins
  • Gearboxes
  • Turbine casings in the power generation industry

In addition to machining parallel bores, line boring machines can also be used for tapering holes and for machining the outside face of the work piece using a facing head.

See MLB610 Line Borer Specifications


Image above: Example of a line boring machine using a facing head


What bore sizes can they machine?

The bar feed type of Line Boring Machine, such as the LB3060 is capable of machining bores as small as of 1.5” and up to 24”

The larger carriage feed type of machine is suitable for job sizes from 6” up to 80” diameter.

Power Pptions

Most line boring machines can be hydraulically powered, but many others can also be pneumatic or electrically powered.

Feed Rates

These are normally infinitely variable from 0-25mm per minute and a hand feed revolution of 2mm

What makes a good portable line boring machine?

They should produce workshop quality tolerances on site, they must be quick and easy set up yet be robust in design and construction. Some machines such as the LB100 & LB150 incorporate a hollow boring bar which allows laser alignment.



Laser alignment is possible if the line boring machine incorporates a hollow bar.


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