I was routing some tracks for a marble game
experiment and was getting messy cuts and some burning. I figured, the
router bit is probably getting too dull.
To sharpen carbide cutters, you need a diamond wheel. Proper diamond wheels are
quite expensive. I once tried using a diamond tile saw blade.
It cut the carbide, but far too rough.
I also tried a diamond stone one time, but that was slow and tedious.
A reader, Andrew Scott, had suggested using a Dremel tool with a diamond
wheel to sharpen carbide saw blades. Dremel tool diamond wheels are
relatively cheap. I tried it, and it seemed to work. The diamond wheel
was just fine enough for sharpening.
It's really quite simple. The most useful piece of information I can give
you is that it actually works!
I first sharpened just the flat part of the cutter, and it
cut much better after that.
Later, I accidentally routed into a screw in my jig, so I sharpened
again, this time sharpening the outside edge as well.
Although for round-over bits and other bits with inside curves,
a wheel really wouldn't work that well.
I have since been told that dust from sharpening carbide
is hazardous to your health, so I'd recommend doing this outside
on a windy day. Though I suspect, as a hobbyist, only sharpening
the occasional bit, the dust exposure is still less than in
it would be for someone sharpening blades professionally,
even with protective equipment.
And this is the jig I was using to route out those tracks.
I'm using my 3D pantograph,
with a 3D template to cut some ramps for a
marble toy experiment.
Before and after.
You can see some lines along the grooves in the track pieces at right. Those are from
pre-routing a square channel to make less work for the ball nose bit, but I routed
some of those too deep.