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How to use Simple Geometry to Align Complex Machines – Part 2

Proper alignment is a core requirement for industrial processing equipment. In this blog series, we are learning to speak the "language" of machine geometry to bridge the communication gap between machinists and metrologists. By representing components as geometric entities, we clarify the alignment requirements and define which instrument is best suited for the task. 

Planar Applications

Many alignment challenges require setting a machine surface in a specific orientation. For example, sole plates and machine bases must be level. Mill stands and vertical ways must be plumb. Portable mill rails and deck pads have precise flatness callouts. Surfaces like these are often characterized by a plane and set the primary datum for additional machine components. Effective devices for establishing level, plumb, and flat (non-level) planes are precision sight levels and jig transits.  

Level alignment of rollsFoundation leveling with a Brunson 545-160Checking machine surface plumb with Brunson 771 Jig Transit
Left and center: A precision sight level checks rolls for level and a surface table for flatness. Above right: A jig transit sets a machine surface plumb.
Brunson 545-190 precision sight level

A Precision Sight Level (545-190) sweeps level and flat planes.

Brunson 771-H190 Jig Transit

A Jig Transit (771-H190) sweeps horizontal (level) and vertical (plumb) planes.













Precision sight levels are optimized for sweeping horizontal planes that are precisely level by using a built-in split-bubble vial. (It can also sweep non-level planes if desired.)  Once the instrument is set to sweep the desired plane, scales are mounted in various positions on the machine and readings taken to determine how level (or flat) the surface may be. Machine adjustments are made by watching the scales with the level, providing immediate feedback to the person doing the adjustment.

Making things vertical is almost as easy as making them horizontal. To do this job, however, we use a transit rather than a level. We set the vertical spindle of the instrument perfectly vertical – as in “exactly parallel to gravity”, not just pointing generally “up and down”. Once we do this, we know that the telescope will rotate through a true vertical (plumb) plane, regardless of what azimuth (horizontal) direction that plane is oriented. Common planar measurements include:   

  • sole plates
  • thrust bearings for turbine shafts in hydroelectric applications
  • machine ways, horizontal and vertical
  • engine frames
  • carriage rails
  • machine ways on portable mills
  • swing racks and deck pads on dragline excavators
  • rollers of all sizes
  • aircraft and automotive fixtures

Learn more about how planar measurements can guide the installation
and inspection of machine components by visiting our knowledge base. 

View Our Knowledge Base


Want to know more about Machine Geometry? Read the rest of the series by clicking one of the links below:

Understanding Machine Geometry and Alignment

How to use Simple Geometry to Align Machines with Optical Instruments – Part One

Matt Settle
By Matt Settle on Feb 25, 2016 9:20:36 AM

Topics: Metrology, Optical Tooling, machine geometry

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The Brunson blog is designed to be a platform for collaborative exploration in the field of metrology. You can expect to explore new Brunson products, hear from industry professionals invited to be contributing editors, and gain insight from customers who use Brunson products. So if you are one of the chosen few people who understand that Metrology is not a study of the weather, please join us here.