Categories: Shaft Alignment,Machinery Maintenance,Other Topics

The Role of Fasteners in the Alignment Process

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By on January 24, 2018

Fasteners are a critical component of the precision shaft alignment process, yet the importance of fasteners is many times overlooked.  If bolting is not selected, assembled, and torqued correctly, it can make the precision shaft alignment process less accurate, more difficult to achieve, and potentially harmful to the machines.

While there are always unusual circumstances, normally machines are bolted together using this process.  Whenever you are unsure, please consult your machine designer or engineering department.

BOLT – a fastener used in conjunction with a mating threaded nut or plate.  It is used to apply force to two or more components to attach firmly, and to prevent unwanted movement.  It should go through the top of the motor foot.

FLAT WASHER – provides a surface against which the head of the bolt, and the face of the washer contact.  A flat washer increases the loading area of the bolt and nut, prevents damage to from the machine foot or base caused by turning the fastener, and spans the hole thru which the fastener goes.

LOCK WASHER – a helical spring or toothed washer which serves to retard movement due to inadequately tightened fasteners.

NUT – a block, with a threaded hole, normally hexagonal, into which a bolt is threaded for the purpose of clamping force.

Establishing and maintaining a proper tightening sequence is critical to precise alignment.  Bolts should be tightened in a crisscross pattern, like a pipe flange or head gasket.

You should also tighten in several passes, adding more torque with each pass.  This will help minimize any unintended movement of the machine while tightening.

About the Author

Stan Riddle joined VibrAlign in 2008. He has over 35 years experience in aligning industrial machinery. Stan received his AAS Degree in Machinist Technology from Surry Community College in Dobson, NC, and also holds a diploma in Industrial Systems Technology from Forsyth Technical Community College in Winston-Salem, NC, where he was also an instructor in the program.

Stan began his maintenance career working as a machinist and millwright for companies such as Weyerhaeuser, R.J. Reynolds, and Tyco Electronics. He also has over 25 years experience in Predictive Technologies, such as vibration analysis, thermography, oil analysis, and ultrasonic inspection. He is a certified Level III Vibration Analyst with the Vibration Institute, and is a Past Chairman and Board Member of the Piedmont Chapter.

Stan and his wife live in Yadkinville, NC.

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