Millright CNC Mega V XXL

About the Machine

Millright CNC no longer sells this model, but it remains fully supported in Easel. The Mega V XXL has a 1270 x 1270 x 95 mm (50 x 50 x 3.75 in) working area, a 120V, 1.25 horsepower Makita RT0701C router, and rack-and-pinion drive on X and Y with a lead screw and anti-backlash nut on Z. Millright CNC's archived page for this model does not state a controller or firmware. Assembly is required; expect a full weekend for this large machine.

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 Mega V XXL's 120V, 1.25 horsepower Makita RT0701C router doesn't have a published RPM on this page, check the router's own speed dial against the chart. Its rack-and-pinion X/Y drive is real mechanical advantage that resists deflection better than a lead-screw desktop machine, but it's still a router, not an industrial spindle. 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. On a machine this large, take shallower passes and build up gradually. 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 Mega V XXL's Makita router has no published RPM on this page, 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.