If you were a woodworker, the thought of sharpening router bits should have crossed your mind at least once, but is it really practical or possible to sharpen your router bits?
Now, we all know that router bits are expendable, they wear and will get damaged when you use. Your router bits will not last forever. It will get blunt after time so do not be afraid to replace it after it has given its life for your work. Consider reading these guides to pick the best router bits and best router table to your need. If you already have a router bit set, learn cove and Stick technique, how to clean, working with router table bits and how to use router bits, I’m sure it’ll be helpful to you.
Having said that, after years of working with router bits, I’ve learnt that you could maximize your investment of sine carbide tipped bits if the flat surfaces were honed in the right way after use.
Warning: do not hone the bevel. The thing with router bits is that they must be well balanced so that they are able to spin at their high operating speed. Even the slightest difference in the amount of material removed from one side of a bit than the other will unbalance the bit and create dangerous vibration.
So what is the best way to hone carbide?
Honing carbide does require diamond wetstones. Most of the time, you will need three progressive grits, coarse 325 grit, fine 600 grit, and extra fine 1200 grit. They can be used dry, or lubricated with water, or light oil, such as WD-40. You place the flat surface of the tip on the stone and slide it along the stone. If the bit has two or more tips, make the same number of equal-length strokes and with the same light pressure to each face to avoid unbalancing the bit. Also as you move to the finer grits, reduce pressure so as not to dislodge the diamonds from the bonding surface.
If you have a bit that you can’t restore by lapping the face, consider sending it to a sharpening service. The results could be varied and do not expect absolute quality bits as you can never be sure of their expertise. If in doubt, you should send only one or two bits to sharpening service to “test”. Before sending your bits to sharpening services, consider the cost of the service and postage, sometimes it is cheaper and better just to replace your bits and get a new set.
What about HSS bits? For this type of bits, you will need to lap the flat surfaces on fine-grit waterstones. Now, do the same amount of work to each surface to maintain balance.
Last words: Consider leaving this work to professionals before playing with your expensive bits. Each time your bit is honed, it gets slightly small in diameter. It can change the size of the joint or profile if you do not do it properly. Take care of your bits and do not wait until it gets dulls and burn the wood in spots and abrades, send your bits out for grinding the minute they start to lose performance. Treat it well and you will have a much better woodworking life.
Check out this video for more on cleaning, maintaining and sharpening your Router Bit from MPOWERTools