How is the shaft centerline height from the bottom of the feet determined from the frame size?

• A. The frame size height is determined by the last digit.
• B. The first two digits divided by 4.
• C. The second digit multiplied by 2.
• D. The entire frame size divided by 8.

Answer: (B)

The shaft centerline height is derived from the frame size by using the main two-digit size as the basis and applying a fixed conversion. Specifically, take the first two digits of the frame size and divide by four. This creates a consistent, proportional height measurement from the bottom of the feet to the shaft centerline.

Using the last digit would ignore the overall size, and multiplying the second digit by two or dividing the entire frame size by eight would distort the established relationship between frame size and centerline height. For example, a frame size of 52 would yield a centerline height of 13 (in the appropriate units), and a frame size of 56 would yield 14.