This is great! I appreciate the thoughts...and it has made me aware of a few issues. Heck don't worry about criticism....lay it out there....whatever comes to mind. It is much easier to change now then later.
CL, I wasn't aware of the speed issue, and after looking at the Burrking Knifemakers attachment, it also comes with a 5" contact/drive wheel. I didn't think about it earlier.....but heck, why not just use the original 5" wheel.
Mike, great point about the center wheel adjustability. I played with the idea very earlier and talked myself out of it. The reason is that the tension is easily adjusted with the top roller...so no need to move the middle roller for tension. The reason for the center roller is to shorten the span of unsupported belt,... to provide a flatter grind. I placed it close to the drive roller thinking that most your work will be grinding somewhere on the belt face in between these two wheels. Then if you need more slack/convex shaping, you can move up a bit and work in between the top roller and the center roller...then for the most convex/slack, simply remove the center roller.
...hmmm, now you have me second guessing myself.....maybe I just need to build one of each and see.
In the design above, it may be hard to pick up on, but the center roller is slighty out in front of the other two rollers. This pulls the belt out about .100" from where it would normally run.
Laurence, Great point about the tensioning! This has the same system that the KMG1 and BaderIII attachment uses. The details are not drawn in this CAD model but it is very quick. There is a tensioning screw on the top roller that when tightened will pull the roller up to tighten the belt...it works very nicely with a "t" handle allen wrench.
Nick,
I haven't thought much about the price at this point....the first thing for me is to make sure it is a good product. I have a few makers lined up to put the prototypes to the test. I'd say that after they run them for a month or so and we tweek the design as needed...then everything else will fall into place. Your just like a kid!

" can I have it now, can I have it now, can I ha...."
Thank you for the note!
Jim,
Thank you for the kind words! I have plans for a square wheel design. Hopefulley it will fit your BEE. But I can't get to it for a few more months though.
Keep the comments coming. Don't worry about criticism...or bruising my ego or telling that I have an ugly baby.

....(hee hee). Your "off the cuff" comments and ideas are very valuable!
Thanks,
Rob