Router bits are essential tools for shaping, cutting, and detailing wood and other materials. With hundreds of options available, understanding the basics of router bit design and selection can help you choose the right bit for your project.
What Is a Router Bit Profile?
The profile of a router bit refers to the shape of its cutting edge, the part that makes contact with the workpiece. Common profiles include:
- Straight
- Flush trim
- Round-over
- Roman ogee
- Rabbet
- ...and many more.
Each profile serves a specific purpose, from trimming and joining to creating decorative edges.
Router Bit Materials: HSS vs. Carbide
Router bits are typically made from either High-Speed Steel (HSS) or carbide.
- HSS Bits
- Lower cost
- Easier to sharpen
- Dull more quickly
- More flexible (less prone to chipping)
- Carbide Bits
- Stay sharp much longer
- More brittle—can chip or shatter if dropped
- Typically brazed onto a steel body, although solid carbide options exist
- More expensive than HSS, but longer-lasting
Router Bit Components
Shank – 1/4" or 1/2" solid shaft portion of the router bit installed into the router’s collet and secured with a collet nut.
Shank Diameter – Shank diameter is the width of the router bit shaft. This is an important measurement to determine the proper cutting speed, suitable cutting depth, and whether the bit is the appropriate size for the router.
Body – Contains the cutter or cutters that shape or cut the workpiece.
Cutting Edge – Removes material from the workpiece.
Fluted Body – Consists of the cutting edges, and grooves/gullets milled into the router bit body. The flutes are responsible for evacuating chips and debris from the workpiece.
Finish – Teflon coating (PTFE), paint, or powder coating used by some manufacturers to reduce friction, pitch build-up, and to help event rust.
Ball-Bearing Guide (Pilot) – Used on flush-trim and pattern bits as a guide to rout one surface flush with an adjoining surface.
Shank Sizes: 1/4” vs. 1/2”
Router bits come in two main shank sizes:
- 1/4" shank – Common on small or compact routers. More affordable, but more prone to vibration and breakage.
- 1/2" shank – Preferred for most applications. Provides:
- Greater stability
- Less vibration
- Smoother cuts
Choosing Quality Router Bits
With so many brands and options available, selecting a quality bit can be challenging. Price alone isn’t always a reliable indicator—so what should you look for?
Factors That Affect Bit Price
- Country of manufacture (e.g., U.S., Europe, Asia)
- Grade of carbide used
- Anti-kickback design
- Number of flutes
- Guide bearing quality
- Coating (e.g., Teflon)
How to Visually Inspect a Router Bit
Before buying, check for:
- Consistent and even carbide thickness
- Clean brazing between the carbide and body
- Smooth cutting edges
- Even paint or powder coating
While cosmetic flaws don’t always affect performance, poor appearance can indicate subpar manufacturing quality.
Manufacturer Reputation and Performance
Even within a single brand, quality can vary by product line or manufacturing batch. The best way to evaluate a router bit is by using it. Look for brands with strong reputations and customer reviews. If you’re unsure, consider:
- Starting with a few bits to test their performance
- Avoiding extremely low-cost bulk sets
- Watching for user feedback in woodworking communities
Summary
| Feature | HSS Bits | Carbide Bits |
|---|---|---|
| Cost | Lower | Higher |
| Durability | Lower | Higher |
| Sharpness Retention | Shorter | Longer |
| Sharpening | Easier | Not usually required |
| Brittle | No | Yes |
| Best For | Occasional/light use | Frequent/heavy use |
Still Not Sure Which Bit to Choose?
If you're new to routing, consider starting with a basic set of profiles like straight, round-over, and flush trim. These will cover most beginner projects. As your skills grow, you can expand your collection to include more specialized bits.