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Key considerations when choosing a line boring machine


The task of selecting a line boring machine for in-situ machining projects requires careful thought and consideration. Even for an experienced field machinist the number of options and modules available can seem overwhelming.

See Line Boring Machines

Pre-configured line boring machines can be purchased ‘off the shelf’, but a more considered approach is to think of a line boring machine as a range of configurable options from a long list of modules. You’ll probably have a clear idea of what you need for a short term project, but by thinking ahead now to your future needs you’ll be armed straight away with the equipment ready to handle a wide range of machining projects.

Let’s take a look at the main considerations for choosing a line boring machine

What type of line boring projects do you intend to work on?

This may seem an obvious question, but line borers are available in many different sizes and with a multitude of different accessories. If you’re looking to refurbish construction vehicles, a smaller model such as the MLB610 is a good choice for machining bores in the hinges of excavators, front loaders, back hoes and dumper trucks.

When doing this type of work you should consider a machine which allows facing as well as machining of the bore. If you want to insert a collar into the machined bore and then machine back to the original specification then a bore welder can be used.

If you choose the Mirage MLB610, depending upon the options you select you’ll also be able to machine larger bores up to 24”. This opens up new possibilities for machining projects such as transfer gearboxes in industrial plants, ship stern tubes, and rolling mills in steel, plants. Selecting different options such as bar diameters, bar lengths, boring arm mounts and drive types will allow you get a machine configured to your exact needs.

For machining turbine casings in power plants the large line boring machines MLB915, MLB2000, MLB3000 and MLB4000 are better suited to these much larger projects.

What size of machines are available?

Within the Mirage range of line boring machines there are machines which can bore diameters as little as 1.5” and others capable of boring up to 157.”

What axial-feed (stroke) do you require?

When refurbishing construction vehicles, the stroke required will be small. The lead screws available with the MLB610 Line Boring Machine will be sufficient for this type of work. This machine type uses a ‘bar feed’ configuration which utilizes separate lead screws available in 12”, 24” and 36” lengths.

The larger Mirage Line Boring Machines use a ‘carriage feed’ configuration, where the leadscrew is situated in a recess within the boring bar. This allows the boring arm to traverse across most of the length of the boring bar (which can be several metres depending upon the boring bar length chosen!).

What power options do you need?

Smaller line borers are typically available with a choice of pneumatic, hydraulic and electric motors. If the Mirage MLB610 is on your shortlist you may wish to consider ordering more than one motor type which will broaden the opportunities for machining in different environments.

Due to the weight of larger line boring machines, these are usually available with hydraulic motors powered by a hydraulic power pack that deliver the necessary torque.

How will your line boring machine be mounted?

Consider if you need set up cones to aid installation and whether you want to use sacrificial mounting posts tack welded to the job, or bolt through the mounting plates.


For smaller line borers, consider buying collets sets. These enable your existing drive, feed, mounting plates and accessories to be used on different bar diameters.

The above is just a quick overview of the key areas to consider. You will find full specifications of machines on our website and if you need assistance a regional representative will be happy to help.

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