Checking Shaft Conditions Machinery's Handbook, 31st Edition
705
For Fig. 3b, let L = 22.28 and D = 3.40, then
. 2720 35645 131 2 . . = =
. 8 340 2228 340 . . # −
h
^
=
R
Checking Shaft Conditions Checking for Various Shaft Conditions.— An indicating height gage, together with V-blocks can be used to check shafts for ovality, taper, straightness (bending or curving), and concentricity of features (as shown exaggerated in Fig. 4). If a shaft on which work has been completed shows lack of concentricity, it may be due to the shaft having become bent or bowed because of mishandling or oval or tapered due to poor machine conditions. In checking for concentricity, the first step is to check for ovality, or out-of-roundness, as in Fig. 4a. The shaft is supported in a suitable V-block on a surface table, and the dial indicator plunger is placed over the workpiece, which is then rotated beneath the plunger to obtain readings of the amount of eccentricity. This procedure (sometimes called clocking, owing to the resemblance of the dial indica tor to a clock face) is repeated for other shaft diameters as necessary, and, in addition to making a written record of the measurements, the positions of extreme conditions should be marked on the workpiece for later reference.
Geometrical Form Desired
Check for Ovality a
Bent or Crooked
Check for Taper b
Check for Bent Shaft c
Curved or Bowed
Check for Curved Shaft d
Tapered
Check for Concentricity
Eccentric
e
Fig. 4.
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