Inventables Carvey

About the Machine

Inventables no longer sells this model, but it remains fully supported in Easel. Carvey is a fully enclosed desktop CNC with an 11.6in x 8in x 2.75in (29cm x 20cm x 7cm) working area and a 300W DC spindle running at 12,000 RPM, using an ER-11 collet for 1/8in shank bits, swappable to 3/16in or 1/4in shanks.

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.

Carvey's enclosed 300W DC spindle runs at a fixed 12,000 RPM, below most of the chart, so leave it there for everything and control the cut with feed rate instead of spindle speed. If acrylic starts to melt, speed the feed up instead of trying to slow the spindle. This is a small, fully enclosed desktop machine, not a rigid production tool, so depth per pass is limited. 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. Carvey's small enclosed build falls well short of that bar, and the fix is simple: take shallow 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, but Carvey's spindle tops out at 12,000 RPM, so run 12,000. With the bit maker's 0.025mm per tooth (0.0010 in): 12,000 x 0.025 x 2 = 600 mm/min (24 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.