Shaft alignment can be carried out in a lot of different ways. Everything from strings, straight edges and feeler gauges to laser shaft alignment systems can be used. We know that dial indicators has been, and still remain, the most common tool to use, and we are going to focus on this here.
To consider when it comes to choosing dial indicators
The bearings in the movement can be either jewels (rubies or sapphires), or brass bushings. Jewels are preferred for heavy use while they last longer.
Metric or imperial; Dials is available with either metric or imperial graduation. The stem, which is the preferred attachement point, is in US most common with a 3/8″ diameter while outside US the 8mm diameter is standard.
Dial size; When working wit dial indicators for shaft alignment the weight of the dial is more important then the actual size. With a larger dial you will also get a heavier dial. This will have an impact on your bar sag.
Balanced vs Continuous dials; Balanced dials runs from zero to a high number, while a Continouos dials starts at zero and runs around the clock. A rev counter keeps track of how many revs the continuous dial makes
Digital vs Mechanical; Digital dials are great in many aspects. For shaft alignment, where you will have a need for halfing the value during the measurement process, we have not found any suitable digital dials on the market.
For more information on the different dials, check out Long Island Indicator’s website