Using a router to add polish and character to your woodworking projects is one of the best and most efficient ways to do so. But dull router bits, on the other hand, will leave unpleasant messy burn marks on your wood. Leaving you to sand them away or maybe even start over.
Can Router Bits be Sharpened?
But can router bits be sharpened? The answer is yes, but with exceptions.
High-quality carbide router bits are generally a lot more durable than high-speed steel (HSS) router bits. If you are considering purchasing tools to sharpen HSS router bits, I would suggest not doing so. It might better to buy another HSS bit because they are fairly cheap.
Most carbide router bits can be sharpened, but in some cases, it’s not recommended. As you can see on the graph below, when we sharpen router bits, what usually happens is that the diameter of the blade gets reduced, as the dull part of the surface gets removed.
Depending on the kind of project that you are working on, it can create some annoying inconveniences. For example, rail & stile and tongue and groove bits. If we try to sharpen these pattern bits, what ends up happening is that the profile of these bits would be changed. For bits that come in pairs, the end product won’t be able to fit into each other anymore. If we look at flush trim bits, the bearing might not be able to line up with the blade after sharpening is done, as the diameter gets reduced.
And as for straight bits and dovetail bits, if we wanna make dado or dovetail joints, we need to keep in mind that the cutting diameter of these blades has been changed. If your dovetail router bit had a 3/4” cutting diameter before sharpening, it might get reduced to somewhere around 0.73” afterward. Examples go on and on.
Some of you reading this article might be looking into sharpening your straight or spiral bit. Straight bits are generally a lot easier to resharpen compared to spiral bits, which is one of its advantages. For spiral bits, you might want to ask your local professional sharpening services to see if they could do it for you.
How to Sharpen Router Bits
Sharpening router bits are actually pretty easy to do, doesn’t require much skill or time. Most of you reading this article are probably thinking about sharpening your bits at home. There are many ways to do so at home. One of my favorite way to sharpen is to use a diamond hone and some lapping fluid. Which you can find on sites like Amazon for less than $40 in total. There are also specialized kits available on the market.
Step 1: Set up
For high-speed steel, you’d want to use a 300-400 grits diamond hone, and for carbide router bits. 600 grits is generally recommended. Then place the stone facing up on the edge of your work surface, feel free to use a clamp to stabilize it. Squirt on a little bit of the lapping onto the surface.
Step 2: Sharpening
Apply a little bit of pressure just to keep the bit stable, then stroke back and forth about 10-15 times. And apply the same method to other cutting surfaces if needed. But remember to use the same amount of force and strokes, so that all cutting blades will have uniform sharpness and shapes.
The same steps can be applied to your bit shank, as it could get stuck inside the router if it’s too rusted.
Alternative Method to Sharpen Router Bits
Another method to sharpen is to use rotary tools and diamond wheels. You can use this combination if the router bit blade is hard to reach with a hone. Both of these are fairly inexpensive as well. The total comes to about 35 dollars, and a lot of you probably already own rotary tools at home.
Read further on how to choose your router bits here: Complete Beginner’s Router Bits Buying Guide