Millright CNC M3

About the Machine

Millright CNC no longer sells this model, but it remains fully supported in Easel. The M3 has an over 260 x 260 x 50 mm (10.25 x 10.25 x 2 in) working area, a bundled Makita RT0701C router, 9mm fiberglass-reinforced GT2 timing belts on X and Y with V-slot rails, a belt-driven Z axis on linear rods for fast lifts, and NEMA 17 stepper motors.

Cut Settings on this Machine

Every cut starts with one formula: Feed Rate = Spindle Speed (RPM) x Chip Load x Number of Cutting Edges (flutes). Chip load is the thickness of material each cutting edge removes in one revolution of the bit. This number comes from the manufacturer of the bit, which publishes a chip-load chart for each bit diameter and material. Look up your exact bit and material, start from the middle of the published range, and you have the third number in the formula. The chart below shows the recommended spindle speed for each material and bit type.

The M3 ships with a Makita RT0701C router, but Millright CNC doesn't publish its RPM on the product page, check the speed dial on the router itself against the chart. Its GT2 timing belts on X and Y and belt-driven Z axis make it a light, fast machine, not a rigid industrial one. A truly rigid machine with a powerful spindle can cut as deep as the bit is wide in a single pass, but that takes real spindle torque, a drive train and clamps that hold firm, a gantry that will not flex, and enough mass to soak up vibration. The M3 falls short of that bar, so take shallower passes. Push too deep and the bit deflects and chatters, leaving scalloped edges, or it rubs instead of cutting and burns the material. The fastest way to dial in a cut is to see what has already worked for other people.

Worked example for feed rate: 1/8in (3.175mm) two-flute solid carbide end mill in hard wood. The chart says 16,000 RPM. The M3's bundled Makita router has no published RPM, so check its speed dial and use that number if it differs from 16,000. With the bit maker's 0.025mm per tooth (0.0010 in), at 16,000 RPM: 16,000 x 0.025 x 2 = 800 mm/min (31 in/min) feed. For depth per pass, start shallow and check Community Cut Settings in Easel for what works on this machine. If the cut sounds strained, reduce the depth, not the feed. Slowing the feed below the chip load makes the bit rub instead of cut.

Community Cut Settings shows the spindle speed, feed rate, and depth per pass other makers actually run for your machine, material, and bit.