Mini Mill Comparison

This chart compares the specifications of the major brands of the mini mill. Bold rows highlight what we feel are significant differences, rather than mistakes or variations in measurement.

Mini mills are sold by, Grizzly, Harbor Freight, and Micro-Mark Grizzly Industrial, Inc. Harbor Freight Tools Micro-Mark
Brand HiTorque SIEG Grizzly Central Machinery MicroLux
Model 3990 X2D G8689 44991 84630
Price Lookup Lookup Lookup Lookup Lookup
Head Tilt Solid Column Solid Column 45°-0°-45° 45°-0°-45° 45°-0°-45°
Head Support Gas Strut Gas Strut Torsion Spring Torsion Spring Torsion Spring
Table 4.7″ x 18.1″ 4.7″ x 18.1″ 3-5/8″ x 15-3/4″ 3-11/16″ x 15-7/8″ 3-3/4″ x 16″
T-slots 12 mm (7/16″) 12 mm (7/16″) 12 mm (7/16″) 12 mm (7/16″) 12 mm (7/16″)
Spindle Taper R8 Taper R8 Taper #3 Morse Taper R8 Taper R8 Taper
Drilling Capacity 0.5″ 0.5″ 0.5″ 0.5″  
Face Milling Capacity 1.2″ 1.2″ 1″ 1″  
End Milling Capacity 0.6″ 0.6″ 1/2″ 1/2″  
Swing 12″ 12″ 12-3/4″ 12″ 12″
Spindle Clearance 11″ 11″ 11-1/2″ 12-1/4″ (10 1/2″ measured) 10″
Z-Axis Travel 10.6″ 10.6″ 7.5″ 8.5″ 7″
X-Axis Travel 11.8″ 11.8″ 7-5/16″ 9″ 8″
Y-Axis Travel 5.1″ 5.1″ 4″ 4″ 4″
Spindle Speed 0-2500 RPM 100-1100, 100-2500 RPM 0-1100, 0-2500 RPM 0-1100, 0-2500 RPM 0-2500 RPM
Motor Controller Brushless DC PWM PWM PWM Brushless DC
Horsepower 0.67 HP
(500W motor)
0.47 HP
(350W motor)
0.47 HP
(350W motor)
0.47 HP
(350W motor)
0.67 HP
(500W motor)
X & Y-Axis Dials 0.0625″ / Turn, 0.001 Graduations 0.0625″ / Turn, 0.001 Graduations 0.0625″ / Turn, 0.001 Graduations 0.0625″ / Turn, 0.001 Graduations 0.050″ / Turn, 0.001 Graduations
Z-Axis Dial 0.060″ / Turn, 0.001 Graduations 0.060″ / Turn, 0.001 Graduations 0.060″ / Rev, 0.002 Graduations 0.060″ / Turn, 0.001 Graduations 0.060″ / Turn, 0.001 Graduations

All the mini mills listed on this page are made in the same factory in China. Except where they have different features, the parts are interchangeable. In our experience there is not a noticeable quality difference between the brands. HiTorque Mini Mill is the best in its class. It has the most power, most torque, and a larger table than other mills in its size range.
The solid column was specifically designed for to maximize rigidity. The column bolts solidly to the base with four cap screws and the wall thickness of the column is significantly greater.
The 500 Watt (0.67 hp) brushless spindle drive motor provides tremendous low end torque. And you can vary the speed from 50 RPM to 2500 RPM continuously. There are no gears to shift. And, with no gears, the HiTorque Mini Mill is the quietest in its class.
The large mill table provides 50% more table area than other mini mills. It also has 30% more travel in each direction. The resettable feed dials allow you to zero them at any point. carries the SIEG X2D Mini Mill. This mini mill has a larger table than other mini mills in its size range and features a 350 Watt DC motor with two spindle speed ranges. The air spring head support gives it more Z-axis travel than most other mini mills.

Grizzly Industrial, Inc. sells the Grizzly model G8689 mini mill. The Grizzly mini mill has a 3 Morse taper spindle. It comes with two 3 Morse taper collets; a 3/8 inch collet and a 1/2 inch collet.

Harbor Freight Tools distributes the Central Machinery model 44991 mini mill. The Harbor Freight mini mill has an R8 spindle.

Micro-Mark also carries the MicroLux model 84630 R8 mini mill. The MicroLux mini mill has one unique feature; the table feed dials both advance 0.050 inch per revolution. On all the other mini mills the dials advance 1/16 inch per revolution. The 0.050-inch per turn is easier to use than the 0.0625-inch per turn of the other mini mills. Micro-Mark will have you believe that the other mini mills have metric dials, but they do not. This mini mill features the 500 watt brushless DC drive system.

Homier Mobile Merchants previously distributed the Speedway mini mill model 03947. The Homier mini mill has an R8 spindle. (Cummins Industrial Tools) previously distributed the mini mill model 7877. The ToolsNow mini mill has an R8 spindle.

This information is put together from published specifications and by measurements made by users of the machines. It is believed to be accurate, but there are no guarantees.