For those of you looking for an inexpensive way to sharpen carbide this is what I use. I bought a diamond grinding disk for HF. It is one that is used on their saw blade sharpener. Its cheap, if I remember correctly around $8 and $12. The only problem is it only has a 1/2-inch hole so I also purchased a cheap 5-inch bench grinder. The disk is a little coarser than the expensive wheels, but it gets the job done.
I also have some small hand diamond boards or files I use to touch up.
I also have some small hand diamond boards or files I use to touch up.