I wrote the original version of this article 15 years ago and basically re-wrote it so I could present it here, as promised. As usual, I cannot get the post to look like the original so I'm attaching a pdf of the article as written.
A lot of us have small lathes but that doesn't mean they can't knurl well. In my opinion, the biggest impediment to good knurling are the tools we use. The typical straddle knurlers allow too much movement and I know from experience that this is just not good. If you can, try to modify them to improve their rigidity and I think you'll find this improves the quality of your knurls. Or you can build a better knurler from scratch that meets your criteria of what a knurler should be.
I hope this article provides some food for thought. If you would like to reproduce this tool, please feel free to do so.
If there are questions or criticisms, lay it on me!
Mike