I used a file to reshape the edge profile on my m43 when I first got it. Then I got a sanding block from the hardware store that had a nice foam pad on it that I could put various grits of sandpaper. Then it was just sitting on the porch with a glass of single malt or a good stout every night for 30 min and watching the trees blow. Slowly work on the edge. Now that I have the profile I want, I honestly only use the chakma to maintain the edge as I work with it, but it's sandpaper that brings the edge at the end of the day. It's hair-shaving sharp. I used it today to trim some bushes with limbs up to 1.5 in wide. 1 hit chops or multiple small branches in one hit. Still able to slice paper after 30 min (I like to show off to the little lady). After I'm done playing with it for the night, I'll sit back on the porch with my sanding block and bring back that shaving edge. :thumbup: Not sure there is too much that a video would show. You aren't going to break it, so just try. If a shmuck like me can get it, you can!
edit: I am eying one of those belt sanders from Harbor Freight, though. Or better yet a Delta!
it's a 37MB winzip file, unzip it into it's own folder somewhere, click the index.htm to start it in your default browser.
you may need to create an account/log in to download it if the traffic gets too big, for security reasons, or if my IP address changes (if i reboot my router, it might change) you may need a new link as it depends on my IP.