What Can You Make With a Wood CNC Machine?

• 1
  Key takeaways
• 2
  How a router removes wood, and why that decides the part
• 3
  Grain direction and moisture set the real tolerance
• 4
  3-axis, 4-axis, and 5-axis: what each one unlocks
• 5
  Tooling choices and the errors that show up on the part
• 6
  When the part should be machined in metal instead
• 7
  What you can make with a wood cnc machine, by part type

A wood router spins a cutter at 12,000 to 24,000 rpm and moves it along a programmed path. The tool has two or three flutes with a sharp rake angle, and each flute takes a chip between 0.1 mm and 0.5 mm thick depending on feed rate. Metal cutting uses the same math, but the numbers live in a different range.

Wood is not uniform. It is a bundle of cellulose fibers held together by lignin, and it is far weaker across the grain than along it. A cutter entering cross-grain lifts fibers before it shears them, which is why you see fuzz on end grain and clean edges on long grain from the same tool.

The practical result is that part geometry matters more than machine rigidity on most wood jobs. A flat panel with through holes is easy. A thin fin standing 80 mm tall with a 3 mm wall is not, because the fiber bundles at the tip deflect under side load and snap.

Chip clearance decides finish more often than spindle speed does. If the flute cannot eject the chip fast enough, the chip recuts, heats, and burnishes the edge. That shows up as a dark line on the profile, and no amount of sanding removes it cleanly.

Wood moves with humidity. A 300 mm wide oak panel can change width by 3 mm to 6 mm between 30% and 70% relative humidity, and that swing is roughly ten times anything a router table contributes. If your drawing calls for ±0.2 mm on a bare wood panel, the material will not hold it after a season in a warehouse.

The direction of the cut relative to the grain also changes edge quality. Climb cutting, where the cutter rotation matches the feed direction, reduces tear-out on the exit side of the cut. Conventional cutting gives a better finish on the entry side. On parts with two finished faces, run a light finishing pass in the opposite direction at 0.2 mm to 0.3 mm radial depth.

Moisture content at the time of cutting should sit between 6% and 9% for interior furniture stock. Kiln-dried lumber above 12% will shrink after machining and open glue joints or loosen press-fit inserts. Cheap sheet goods often ship at 10% to 14% and stabilize only after a week in a conditioned shop.

For parts that must hold a tight number, design around movement instead of fighting it. Use plywood or MDF where stability matters, and reserve solid hardwood for faces, edges, and details where the grain has to show.

A 3-axis router moves the gantry in X, Y, and Z. The tool always points straight down. That covers cabinet doors, signage, nested sheet parts, mortises, and any pocket you can reach from above. Most production routers sold into furniture shops are 3-axis machines, and they run at the highest feed rates because the frame is simple.

A 4-axis machine adds rotation about one horizontal axis, usually the X axis. That lets you machine a table leg, a column, or a wrapped profile in one setup by turning the blank between operations. It is the cheapest way to break out of flat work.

A 5-axis machine adds a second rotary axis, so the tool can tilt. Undercuts, compound curves, and deep pockets with drafted walls become reachable without flipping the part. Sculpted chair backs, propeller blanks, and carved panels with overhanging detail are the usual candidates.

The trade is setup and speed. A 5-axis machine needs a post-processor that understands your CAM output, and the tool tip moves slower because it is following a longer path. If a part can be made on three axes with one flip, that is usually the cheaper route.

A flat end mill leaves a stepped floor. A ball nose leaves a scalloped floor whose height depends on stepover. For a 6 mm ball nose at 1.5 mm stepover, scallop height on a curved surface is roughly 0.05 mm to 0.1 mm and needs sanding before finish. Drop the stepover to 0.5 mm and the scallop nearly disappears, at three times the cycle time.

Compression bits solve the two-sided tear-out problem in plywood and melamine. The up-cut flutes at the tip and down-cut flutes at the shank pull fibers toward the middle of the board, so both faces stay clean. They cost three to five times a standard bit and should be reserved for visible edges.

Feed and speed errors follow a pattern. Too slow a feed with a high spindle speed burns the wood and dulls the edge. Too fast a feed with a small cutter snaps the tool. A 6 mm two-flute carbide bit in hardwood runs well at 16,000 rpm and 3,000 mm/min to 4,500 mm/min feed with a 6 mm depth of cut.

Hold-down is the most common cause of scrapped parts. Vacuum tables lose grip on small nested parts as the cut frees them. Tabs 3 mm to 5 mm thick, or a onion skin of 0.5 mm left on the last pass, keep the part from moving into the tool.

Wood routing works because the material is soft and forgiving. The same geometry in aluminium, stainless, or PEEK behaves differently. A 3 mm wall that stands fine in oak will chatter in 6061-T6 during a roughing pass unless the toolpath is reworked and the part is supported.

Hardware interfaces are the usual breaking point. Threaded inserts, bearing bores, and dowel holes that must hold 0.05 mm need a rigid machine and a reamed hole. On a wood router the spindle deflects under load and the hole comes out tapered.

At GreatLight we machine the metal side of these assemblies. Our 127 CNC machines include 16 simultaneous 5-axis centers and 12 four-axis mills, with 4,000 mm maximum processing size and a Ø400 mm rotary table. Metal parts hold ±0.005 mm and finishes from Ra 0.8–1.6 μm after bead blasting or anodizing.

A mixed assembly is normal. The wood panel gets routed, the brackets, bushings, and inserts get machined in 6061, 304 stainless, or C36000 brass. Quotation and a free DFM analysis come back within 12 hours, and production can start within 24 hours.

Tooling for wood and tooling for metal do not share a shop floor. Carbide grades, rake angles, and coolant all change. Keep the two processes separate and the tolerances stay honest.