If you’ve ever stared at a wall of router bits in a hardware store and felt completely overwhelmed, you’re not alone. Choosing the correct router bit can be confusing — especially with so many shapes, sizes, and materials out there. But fear not! In this guide, we’ll walk you through everything you need to know to confidently choose the right router bit for your project, understand how different materials affect your choice, and even calculate feeds and speeds like a pro.
Whether you’re woodworking, machining plastic, or cutting aluminum, this is your ultimate beginner-friendly guide.
1. Straight Bits
Use: Cutting straight into the material, making dados, rabbets, and grooves.
Best for: Woodworking (softwood, hardwood), MDF, plywood.
2. Spiral Bits
Use: Smoother, cleaner cuts than straight bits. Ideal for plunge cuts and slotting.
Types:
Up-cut: Pulls chips up; good for deep cuts.
Down-cut: Pushes chips down; good for clean top surfaces.
Compression: Down-cut at the top, up-cut at the bottom — best for plywood and laminates.
Best for: Wood, plywood, MDF, plastics.
3. Flush Trim Bits
Use: Trimming laminate or veneer to the edge of a substrate using a bearing.
Best for: Veneered plywood, laminate, MDF.
4. Chamfer, Round-Over, Beading Bits
Use: Decorative edges.
Best for: Finished furniture edges, cabinetry.
5. Rabbeting Bits
Use: Cut a shoulder on the edge of a workpiece (rabbet joint).
Best for: Joinery in furniture/cabinetry.
6. V-Groove, Cove, and Specialty Bits
Use: Decorative carving, engraving, sign-making.
Best for: Softwood, hardwood, plastics.
Different materials behave differently when cut. Your choice of bit must account for material hardness, chip load, and heat generation.
Wood (Softwood & Hardwood)
Recommended bits: Carbide-tipped or solid carbide spiral bits.
Why? Wood is fibrous and can tear or burn. Sharp bits with clean shearing action are ideal.
Avoid: Dull bits, especially with hardwoods.
Plywood / MDF
Recommended bits: Compression or down-cut spiral bits.
Why? These materials can splinter or fuzz. Compression bits give clean top and bottom cuts.
Note: MDF dulls bits quickly — go with carbide.
Plastics (Acrylic, PVC, Polycarbonate)
Recommended bits: O-flute or single-flute solid carbide bits.
Why? Reduces heat and melting; evacuates chips quickly.
Avoid: Dull or multi-flute bits — they melt plastic.
Aluminum
Recommended bits: Single-flute solid carbide aluminum-cutting bit.
Why? Prevents chip loading and heat buildup.
Note: Use lubricant or air blast to keep cool.
Bit Diameter
Smaller bits (1/8″, 1/4″): Great for detail, slower material removal.
Larger bits (1/2″, 3/4″, etc.): Faster cutting, but more strain on the router.
Shank Size
1/4” shank: More common, cheaper, flexible. More vibration.
1/2” shank: More stable, less vibration, better performance — preferred if your router supports it.
Here’s where most beginners get stuck — feeds and speeds are critical for clean cuts, long bit life, and safety.
1. Router Bit Speed (RPM)
Bits are rated for maximum RPMs. Your router may go up to 30,000 RPM — but using the correct RPM for your bit size and material is essential.
Recommended Speed Table
| Bit Diameter | Max RPM |
|---|---|
| 1/8″ | 28,000 |
| 1/4″ | 24,000 |
| 1/2″ | 18,000 |
| 1″ | 12,000 |
Larger bits must spin slower to avoid dangerous vibration and overheating.
2. Feed Rate (Inches per Minute)
Feed rate = how fast you move the router or material into the bit.
What is Chip Load?
Chip load = thickness of material removed by each cutting edge per revolution.
| Material | Chip Load (inches) |
|---|---|
| Hardwood | 0.005 – 0.015 |
| Softwood | 0.007 – 0.020 |
| MDF/Plywood | 0.005 – 0.015 |
| Acrylic | 0.003 – 0.008 |
| Aluminum | 0.001 – 0.003 |
❌ Using the Wrong Bit for the Material
Wood bits on aluminum? Bad idea.
Plastic bits on MDF? They’ll dull quickly.
❌ Running at the Wrong Speed
Large bit + high RPM = dangerous.
Too slow = rough cuts or burning.
❌ Feeding Too Slowly
Causes burning and tool wear.
❌ Feeding Too Fast
Causes chatter and tear-out.
| Material | Bit Type | Feed Rate Range | Notes |
|---|---|---|---|
| Softwood | Carbide spiral (up-cut) | 150–300 IPM | Sharp tools, faster feed |
| Hardwood | Spiral down-cut or compression | 100–200 IPM | Slower feeds to prevent tear-out |
| MDF/Plywood | Compression bit | 150–250 IPM | Avoid dust-up; use dust collection |
| Acrylic | O-flute, 1-flute carbide | 50–100 IPM | Prevent melting; single flute |
| Aluminum | Single flute carbide | 30–80 IPM | Use lubricant or air cooling |
Final Tips
Always use sharp bits — dull ones are dangerous and burn material. The best CNC router bits at affordable prices (better pricing than ANY other brand on the market) are from Techno CNC Shop. Here you can shop a variety of CNC router bits at low prices.
Match your bit to both the task and the material.
Understand feed rates and speeds — these are more important than brand names.
Start with test cuts — always test settings before final work.
Clean your bits regularly to remove resin and dust buildup.
Recommended Tools & Resources
Feed and Speed Calculators: Try online calculators (e.g., G-Wizard, HSMAdvisor)
Digital Caliper: For measuring bit diameter accurately.
Tachometer: To check actual RPMs on variable-speed routers.
Dust Extraction: Crucial for safety, especially with MDF.
The right router bit is not just about the shape — it’s about:
The material you’re cutting
The cut you want to make
The bit diameter and type
The feed rate and RPM
Understanding these variables lets you work safely, efficiently, and get cleaner results every time.