Router bits are the cutting edge (‘router tool’) we use to ensure each piece of wood has a perfect shape and texture. After a period of use, however, they may become blunt such that their cutting effectiveness is undermined. This means that even after careful finishing, the result will be rough and require quite a lot of follow up treatment to make it right again. Understanding how to sharpen router bits correctly can increase their life, reduce expenses and ensure proper operation.
In this guide we’ll cover the best ways to sharpen various types of bits. We’ll explain why it matters, and give you some pro tips to keep your bits in top shape.
Reasons For Sharpening Router Bits
Dull router bits can cause:
- Tear out and rough edges in wood.
- Increased friction due to heat.
- Burn marks on workpieces.
- Excessive strain on the tool itself.
Regular sharpening makes for cleaner cuts, troubleless operation and a longer life for your bit.
Types of Router Bits and the Way to Sharpen Them
Before we get into sharpening, it’s important to know what router bit style there are and how they work. This is a quick breakdown of the most common router bit types:
Straight Bits – used for cutting grooves and dadoes. When sharpening, the flat surfaces must be honed.
Flush Trim Bits – used to trim edges. Before sharpening a cutting edge, you’ll need to remove the bearing and get rid of any burrs formed by heat treating.
Chamfer Bits – used for bevelling edges. The slanting cutting surface must be put out carefully.
Round-Over Bits – provide rounded edges. Done by special process, since the curved section needs its own type of sharpener.
Rabbeting Bits – cut stepped edges. Before sharpening the bearing and cutting edges you will have to remove the bearing.
Cove Bits – used for decorative grooves. The concave shape will require sharpening with precision.
Each style of router bit has its own needs for sharpening, and it is essential to identify its type before starting.
- If you have a carbide bit, put it on a rotary tool with grinding capabilities.
- A bench grinder with a fine-grit wheel is great for working with high speed steel (HSS) bits.
- You’ll need a magnifying glass or loupe to inspect the edges, to make sure you are really doing a good job.
- Use lubricating oil for a smooth sharpening experience.
- Attach your sharpening jig and set the probe so that it points at what would be perfect 90°.
Sharp Bits: A Step-by-Step Guide to Sharpening Router Bits
First Things First: Clean That Bit!
Before sharpening, use a bit cleaner or soft brush dipped in solvent to clear away any resin, pitch or sawdust built up on your router bit.
Look for Damage
Be suspicious of
- Edges that have chipped (probably needs professional repair)
- Worn-out carbide tips (may better to just replace the bit if they are badly damaged)
- Dull cutting edges (can be restored through sharpening)
Sharpening HSS (High-Speed Steel) Bits
- Use a bench grinder with a fine-grit wheel on high speed steel bits.
- Hold the bit at its original bevel angle (usually 20° – 30°).
- Grind the edge lightly, using only smooth strokes.
- Avoid overheating by dipping the bit in water for cooling off periodically.
- Using a honing stone to polish the edge will deliver a finer finish.
Sharpening Carbide-Tipped Bits
- Carbide is harder than HSS, so use a diamond wheel or rotary tool.
- Maintaining the original angle, only grind the carbide tip.
- Work in short bursts to avoid overheating.
- Refine the edge with a diamond stone.
Honing the Cutting Edges
After grinding, pick up a fine grit diamond stone to remove any burrs and polish the edge.
- •Move in one direction along the cutting edge.
- •Carefully checking for sharpness, gently feel the edge with your finger—it should be smooth but also slightly gripping.
Bits (If You Disassembled It)
If you removed bearings or guides, make sure to put them back on and reclaim your bit before testing it.
How to Keep Your Router Bits in Tiptop Condition
Clear out any resin that may pile up after you use the bit around.
Here’s how to keep it in like-new shape:
- Store in a protective case to avoid damage.
- Use the right speed setting—high RPMs can overheat bits.
- Avoid cutting dirty or nail-embedded wood to prevent premature dulling.
- When to Replace Router Bits Instead of Sharpening
Conclusion
The shaft was warped or bent, leading to vibration in operation.
Understanding router bits explained and knowing how to sharpen them properly ensures long-lasting performance and professional-quality cuts. By reading up on this guide to router bits, you can maintain different router bit types with speed and economy, saving money while enhancing both your hobby results and craftsmanship.
Regular maintenance and proper sharpening techniques will keep your router bits in great shape, so you can approach any project on time and with confidence. Do put the time into caring for your bits—your router will (and so will your workpiece!) thank you.
