CNC Router Feeds and Speeds for Wood: A Beginner's Guide
Feeds and speeds are the two most important variables in CNC routing. Get them right and cuts are clean, bits last, and the machine sounds confident. Get them wrong and you're burning wood, breaking bits, or chattering your way through a workpiece.
The Two Numbers
Feed rate: How fast the bit moves through the material (mm/min or in/min). Spindle speed (RPM): How fast the bit spins.
These two together determine chip load — how much material each flute removes per revolution. Chip load is the real variable you're controlling.
Target chip load = Feed rate ÷ (RPM × Number of flutes)
Why Chip Load Matters
Too low chip load (slow feed, fast spin): The bit rubs instead of cutting. Generates heat, dulls the bit rapidly, may burn wood.
Too high chip load (fast feed, slow spin): Too much force on each flute. Chattering, rough cuts, possible bit breakage.
Just right: Each flute takes a clean shaving. Smooth walls, long bit life, confident sound.
Starting Points for Wood (Wolfpawn 4040 Pro)
These are conservative starting settings. Move up 10% at a time once cuts are clean.
1/4" (6.35 mm) 2-Flute Upcut End Mill
| Material | Feed Rate | RPM | DOC per Pass |
|---|---|---|---|
| Soft pine | 1500 mm/min | 18,000 | 3 mm |
| Hardwood (oak, maple) | 1000 mm/min | 18,000 | 2 mm |
| MDF | 1800 mm/min | 18,000 | 3 mm |
| Plywood (birch) | 1200 mm/min | 18,000 | 3 mm |
1/8" (3.175 mm) 2-Flute End Mill
| Material | Feed Rate | RPM | DOC per Pass |
|---|---|---|---|
| Soft pine | 900 mm/min | 24,000 | 1.5 mm |
| Hardwood | 600 mm/min | 22,000 | 1 mm |
| MDF | 1000 mm/min | 24,000 | 1.5 mm |
V-Bit (60° or 90°)
| Material | Feed Rate | RPM |
|---|---|---|
| Pine/MDF | 1500 mm/min | 18,000 |
| Hardwood | 1000 mm/min | 18,000 |
Depth of Cut vs Width of Cut
Depth of cut (DOC): How deep each pass goes. Start at 25–50% of bit diameter. Width of cut (WOC): Stepover amount for pocketing/surfacing. 40–50% of bit diameter is standard.
Aggressive DOC with conservative WOC is often faster than shallow passes at full width.
Upcut vs Downcut Bits
Upcut: Pulls chips up and out of the cut. Better chip evacuation, cleaner bottom. Top surface may have slight tearout on plywood.
Downcut: Pushes chips down. Cleaner top surface, important for veneered plywood. Chips pack into the cut — use slower speeds and air blast.
Compression: Upcut geometry at the bottom, downcut at the top. Clean on both faces. Only works at full depth of cut.
Reading the Sound
Your ears are a calibration tool. A healthy cut sounds confident — a rhythmic, consistent bite. Problems sound like:
- Screaming: Too fast RPM for the feed rate — rubbing. Increase feed or decrease RPM.
- Chattering/rattling: Loose workholding or too deep DOC. Fix clamps, reduce depth.
- Burning smell: Chip load too low. Increase feed rate.
- Labored, bogging: Chip load too high. Decrease feed rate.
Workholding
No feeds and speeds can compensate for a workpiece that moves. Use:
- T-track clamps with the Wolfpawn's T-slot bed
- Double-sided tape for thin sheet material
- Vacuum table for production work
- Tabs (small uncut bridges) to keep parts from shifting at cut-through