Figure 1-33. The speed dial is letter calibrated through an rpm range of 700 to 5200. Caution: Turn the dial only when the motor is running. When an operation is complete, always turn the dial to 'Slow' before shutting off the Mark V.
The Mark V is equipped with a speed dial that is calibrated by letter through variable speed ranges (Figure 1-33). Correct speeds are important for safety and good craftsmanship. The speed setting is determined by the operation being performed and the material being processed. Speed dial settings for particular operations are given throughout the text. When there is doubt about what speed to use, start with a slow speed and increase it slowly to the point where the operation is going smoothly. The main and upper auxiliary spindles turn from 700 RPM to 5200 RPM. The lower auxiliary spindle turns 1.6 times faster than the other two, or between 1120RPM and 8320 RPM.
The Mark V speed dial settings with the RPM in parentheses that are given throughout the text are for 60 hz operations only. Most owners have the 60 hz machines. If you have a 50 hz machine, use Table 1-ito convert the RPM for 60 hz operations to the proper speed dial settings for 50 hz operations.
Table 1-1: Speed Dial Conversion Chart for 50 hz Operations