Harbor Freight Mini Mill Review [2023] 4491 MellowPine
Spindle. Spindle on HF 44991. The spindle is powered by a 4/5 hp motor and has an R8 taper for holding the cutting tool. Harbor Freight 44991 can work on two different speed ranges of 01100 RPM and 02500 RPM. These two modes are labeled on the machine as low and high. A slower RPM gives more torque with less speed.