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SHIMS 102 – The pitfalls of carbon steel shims.

Stan’s “Shims 101” blog last year provided some great guidelines and reasons for using pre-cut Stainless Steel Shims.  We repeatedly see rotating equipment that is supplied with carbon steel shims under the feet and/or shims of the incorrect size. When aligning machinery with carbon steel shims get rid of them! Measure the old shim thickness…

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The Importance of Roughing-in Machines before Performing a Shaft Alignment.

During our Best Alignment Practices Training classes our staff of VibrAlign Trainers stresses the importance of rough aligning the machines as part of the pre-alignment steps.  The main reason to do so is to minimize the coupling influences on the movable and stationary machine’s rotational shaft center-lines so the final alignment can be completed with…

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In Shaft Alignment, Low Can Sometimes Mean High!

A customer in the northeast US was concerned that his laser wasn’t working properly.  He called into our office stating “the motor shaft is a ¼ inch low at the coupling, but the laser shows I need to remove a lot of shims from the motor feet – both front and rear”.  His thought was…

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Flexible Couplings and Flexible Shafts

Most mechanics are pretty familiar with flexible couplings.  They are designed with an elastomer, or flexible element, which compensates for slight amounts of misalignment through a sliding motion between the coupling hubs and the insert.  However, it is very important to have some idea as to how much the coupling will flex before it begins…

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Aligning Uncoupled Machines

Normally, it is faster and more accurate to perform shaft alignment while the machines are coupled together.  This offers several benefits such as:  Keeping the relative angular positions of the shafts the same allows the technician to align the true shaft rotational centerlines. Coupling Gap is less likely to change while adjusting the moveable machine,…

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Defining Angularity in Shaft Alignment

There are only two types of measurements for shaft misalignment – offset, which may be called parallel or rim, and angularity, which is sometimes called slope, or face. Offset (parallel or rim) is easy to understand. One shaft is simply higher, lower, or to the left or right of the other one. But angularity can…

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Solving Base-Bound and Bolt-Bound Shaft Alignment Problems

If you align machinery for a living then more than likely you have encountered machines that are base-bound or bolt-bound. Base-bound is when the movable machine has to be lowered and there are either too few or no shims under the movable machine feet to accomplish the vertical alignment. Bolt-bound is when the movable machine…

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Dial Indicator Concepts

Do you understand the fundamentals of dial indicators? It is essential to understand the following 3 dial indicator concepts: 1. Total Indicator Reading, or TIR, 2. The Validity Rule, and 3. True Position Sensing. Total Indicator Reading I’ll zero my dial indicator at 12, and then roll it 180 degrees to 6:00. It reads 30…

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Does Using a Torque Wrench Make Shaft Alignments More Accurate?

Some companies have a policy of torquing motor hold down bolts to set prescribed value. While this may be a regulation in some industries, or required on specific types of machines, it really has little to do with the quality, accuracy or repeatability of shaft alignment–if the alignment is done properly. Most millwrights may disagree. This is…

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Small Details Make A Big Difference in Shaft Alignment

Today’s maintenance personnel are tasked to do more in less time so production can resume as soon as possible. As such, aligners of rotating machinery may believe they are saving time by eliminating some steps of the shaft alignment process when in reality the opposite is true. An alignment check was performed on a process…

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Practice Does Make Perfect in Shaft Alignment

* Picture courtesy of V-Tek Associates, http://www.vtekassociates.com/ Practice and repetition are key components to becoming good at anything. Precision shaft alignment is no different. It is a rare day when an important alignment project develops, all pre-alignment conditions are perfect and the machinist is given all the time in the world to do the alignment. The…

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Defining Level vs. Flat

In mechanical trades, most of us have been taught that most installed machines must be installed level and the bases must be flat. But contrary to what many of us think, level and flat are two completely different terms. Level simply means that the machine is parallel to earth, or horizontal. Flat means that the…

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Organizing Your Shaft Alignment Job

One of the great things about being out and about with other shaft alignment professionals is seeing how they get work done. Two recent shaft alignment training classes had some great examples of how to stay organized. During an alignment on a gas compressor a few weeks ago, these guys had to manage shims at…

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