TABLE OF CONTENTS Units with small diameter couplings are most unwelcome to mechanics who know their craft. Such units are often mounted on tobacco tin bases and are notorious for yielding non-repeatable indicator readings.
While both indicators will tend to lie when mounted to a unit with a sponge base , small units are mainly a problem when a face-mounted indicator is involved.
It s briefly mentioned in the Reverse Dial chapter that more dependable readings are to be expected when the largest practical face diameter is used (when doing Rim and Face Alignment) or if doing Reverse Dial, to use a reasonably long span between the two dials. It follows, then, that larger diameter formats for face indicator readings would aid in better work when dealing with very small units.
However, if the coupling is only 2" or so in diameter, the mechanic has little choice but to use all he can of that existing diameter, or does he? See FIGURE (1).
| Note | The primary reason for artificially enlarging the coupling diameter is to get an indicator reading from the largest practical diameter for a more accurate profile of whatever the angular misalignment. However, there is a valid secondary reason. Small diameter couplings frequently disallow proper mounting of the face indicator. A perpendicular mounting is very important. See the chapter: Perpendicular vs. Otherwise |
The number of ways to artificially increase the diameter of a coupling is limited only by the mechanic s imagination and the available material. Almost anything (rigidly mounted)...
