Any way to reduce low speed on bench drill?

Changing the pulley sizes will get you closer to what you want easier than anything else. Put a large pulley on the drill press arbor and a small pulley on the motor.

The motor you most likely have is a 120VAC 1720 RPM, but check the motor plate. If it's a 3450 RPM motor changing motors would cut your speed in half. Some blower motors run around 900 RPM, but they are fractional HP motors and may not have enough torque.

You can use an AC frequency converter, but they're not cheap. This is how most factories are using AC motors as variable speed in place of DC variable speed motors. The converters often go from 10 Hz to 120 Hz which can make a 1725 motor go from about 200 RPM to 3400 RPM

Ken McWilliams

Another possibility for occasional use would be a bracket on the rear of the drill press which would mount a second motor. Run a belt from a very small pulley on that motor to the largest pulley on your present motor. Then another belt from the smallest step on the present motor to the largest on the spindle. The original motor would not be turned on, but would simply be "along for the ride" whenever this arrangement was used.

I suppose you could get really fancy and install a small gearbox of some sort on it where the motor presently is, and the belt the motor to the gearbox. You could get some incredibly low speeds this way, depending on what you hooked up.