Sometimes, during installation, for one reason or another, the two machines just don’t sit right on the baseplates. From baseplate design issues or machine housing quality problems to poor installation practices, one machine ends up being significantly lower than the other. Let’s say, in this case, it is the movable machine (an engine being aligned to a pump). During the rough alignment process, the engine needs to be raised almost a half inch (500 mils).

Instead of using shims to lift the full amount, the best thing to do is to manufacture a soleplate to fill as much of the gap as possible. In the picture below the correction was roughly 425 mils. You can see there is one thick precut shim and two manufactured plates, all close to 0.120″. Best practices as indicated in our Shimming Infographic encourages you to keep the shim count under the feet to four shims or fewer.

Aligning the machine using shims

If you have resources available to manufacture a soleplate and the machine can remain down for the time it takes to fabricate it, the optimal option is to make a 3/8th-inch plate (0.375 mils) carefully milled to be coplanar (both faces parallel to each other) and shim the rest with two 25 mil shims. This would add up to 0.425″ needed for the vertical correction while keeping the number of shims low.

Alternatively, you can explore the option of lowering the Stationary Machine (the pump) or angling it downwards towards the engine slightly, but these solutions likely will be more difficult to implement than just making a nice soleplate for the engine.

Download our Shimming Best Practices Infographic which outlines 7 things to consider when using shims for machine installation or machine alignment plus Step Shimming.

The 5 Do’s and Don’ts of Shimming

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by Adam Stredel CRL

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