Jim Elsey is a mechanical engineer who has focused on rotating equipment design and applications for the military and several large original equipment manufacturers for 48 years in most industrial markets around the world. Elsey is an active member of the American Society of Mechanical Engineers, the National Association of Corrosion Engineers and the American Society for Metals. He is the general manager for Summit Pump Inc. and the principal of MaDDog Pump Consultants LLC. Elsey may be reached at email@example.com.
18. When using washers with the driver, hold down bolts, use a strong washer material (grade 8) and watch the size (diameter). Many people incorrectly think they can make up the difference in a hole size simply by using a bigger washer. If the washer cups warps at all, then it is wrong, and you will have issues with holding the alignment.
19. If you have to open up (enlarge) the size of hole on a driver foot due to being bolt bound, do not open up the diameter more than the radius of the original hole size. It is also acceptable to machine the hold down bolt to achieve more space, but the procedure must be followed correctly. I am sorry I do not have room for that procedure in this article. A good practice is to keep close to the minor diameter, maintain the symmetry and provide a generous radius as stress relief.