A while back I saw a post here on someone wanting to know how to sharpen the blades on the V-cutter tool. After looking it over, and if mine was dull enough to explore a way to sharpen the blades, I came up with this.
The existing rivets would have to be removed with a tool, maybe a Dremel or drilled out carefully. Once the blades are detached, a few passes on a diamond stone would get then back to razor sharp again.
Ah-ha, now to re-attach the blades. In the past, I have had real good luck using hobby store/Home Depot/Lowes brass rod for rivets. They have to be longer than the thickness of the blade and the blade holder arms, so they protrude about 2mm on either side. A few taps with a ball-pein hammer rounds over the brass ends making your own rivets.
Like I said, I've used these homemade brass rivets over the years to make my own lock-pick handles, and other various tool handles.