When I was testing mechanicals to see whether or not I wanted to fool with 'em, I had a tough time sharpening the blades. Found out I couldn't sharpen them properly while installed in the ferrule, so I took the blades out and found out that my fingers were too big to sharpen them in the conventional way. Then I got smart. I got out my fly tying gear. Adjusted my tying vise to where it would hold a blade, clamped it down and used a small diamond hone. Worked like a charm.