What is the appropriate spindle speed to drill a ¼" diameter hole in a 3" diameter stainless steel piece using a high-speed steel drill bit?

To determine the appropriate spindle speed for drilling a ¼" diameter hole in a 3" diameter stainless steel piece with a high-speed steel drill bit, one must consider the recommended cutting speed for stainless steel and the formula to calculate spindle speed.

Stainless steel typically has a cutting speed ranging from 70 to 100 feet per minute (fpm) for high-speed steel bits. The spindle speed (in revolutions per minute, rpm) can be calculated using the formula:

[ \text{Spindle Speed (rpm)} = \frac{CS \times 12}{\pi \times D} ]

where CS is the cutting speed in feet per minute and D is the diameter of the drill bit in inches.

Assuming a cutting speed of about 90 fpm as a commonly accepted average for stainless steel, the calculation for a ¼" diameter drill bit (0.25 inches) would be:

[ \text{Spindle Speed} = \frac{90 \times 12}{\pi \times 0.25} \approx \frac{1080}{0.785} \approx 1375 \text{ rpm} ]

This calculated spindle speed is close to 1700 rpm. However