What is the result of calculating the RPM using a cutting speed of 120 SFPM and a diameter of 3 inches?

What is the result of calculating the RPM using a cutting speed of 120 SFPM and a diameter of 3 inches?

• A. 120 RPM
• B. 160 RPM
• C. 80 RPM
• D. 100 RPM

Answer: (B)

To determine the RPM when given a cutting speed in surface feet per minute (SFPM) and the diameter of the workpiece, you use the formula: \[ \text{RPM} = \frac{\text{Cutting Speed (SFPM)} \times 12}{\pi \times \text{Diameter (in inches)}} \] In this case, the cutting speed is 120 SFPM and the diameter of the workpiece is 3 inches. First, converting the cutting speed into inches per minute, you have: \[ \text{Cutting Speed in Inches per Minute} = 120 \text{ SFPM} \times 12 \text{ inches} = 1440 \text{ inches per minute} \] Next, applying the values to the RPM formula: \[ \text{RPM} = \frac{1440}{\pi \times 3} \] Calculating this gives: 1. First find \(\pi \times 3 \approx 9.42\) (using \(\pi \approx 3.14\)). 2. Then compute \( \frac{1440}{9.42} \approx 152.6\). However, for cleaner calculations, using

To determine the RPM when given a cutting speed in surface feet per minute (SFPM) and the diameter of the workpiece, you use the formula:

[ \text{RPM} = \frac{\text{Cutting Speed (SFPM)} \times 12}{\pi \times \text{Diameter (in inches)}} ]

In this case, the cutting speed is 120 SFPM and the diameter of the workpiece is 3 inches.

First, converting the cutting speed into inches per minute, you have:

[ \text{Cutting Speed in Inches per Minute} = 120 \text{ SFPM} \times 12 \text{ inches} = 1440 \text{ inches per minute} ]

Next, applying the values to the RPM formula:

[ \text{RPM} = \frac{1440}{\pi \times 3} ]

Calculating this gives:

1. First find (\pi \times 3 \approx 9.42) (using (\pi \approx 3.14)).

2. Then compute ( \frac{1440}{9.42} \approx 152.6).

However, for cleaner calculations, using