We had quite a discussion on these several years ago, after Woodsmith came out with one that you built yourself. My memory isn't that good and I didn't scan the posts in the linked forum to find it, but from memory the Woodsmith article as about issue #110 or 111. Again, this is from my old memory that frequently has holes in it. Go to this link and you will find more than you want to know about router turning. I believe near the end, an added gear allowed turning twists in both directions.