Deflection Calculation

Shaft deflection should be considered when choosing the proper bearing and shaft diameter for end-supported systems. Deflection is directly related to the diameter of the shaft, the unsupported length of the shaft, and the type of shaft end mounting that is used.

"Simple" - the end allows some of the shaft deflection slope through the fastening point.

"Fixed& - the ends are constrained from deflection.

NOTE: Fixed end mounting can be accomplished by capturing the shaft end with a length of engagement equal to or greater than 11⁄2 times the shaft diameter.

D = N x W x L3
Where:
N = value from the chart below
W = load in pounds
L = length (in inches) of unsupported shaft section
"N" VALUE FOR NOOK SHAFTS
Shaft Diameter (in.) Simple Fixed
1/4 3620 x 10-9 905 x 10-9
3/8 715 x 10-9 179 x 10-9
1/2 226 x 10-9 56.6 x 10-9
3/4 44.7 x 10-9 11.2 x 10-9
1 14.1 x 10-9 3.54 x 10-9
1 - 1/2 2.79 x 10-9 .698 x 10-9
2 0.866 x 10-9 .0220 x 10-9
3 0.168 x 10-9 .432 x 10-10
4 0.052 x 10-9 .136 x 10-10
Figure 1