OK folks, I have the first "prototype", and as usual there is good an bad news.

The good news is that it came out virtually perfect on the first try. I only want to increase the outside diameter a bit since I want to smooth the surface after the water cut. The combination of button and flat head fasteners are about the same size as the rivets, and look great (won't see them anyway).

THe bad news is that it took longer on the water cutter than planned. The initial estimate for cutting cost was around $50 based on 1" material, but the actual 30mm (I used 1.25) required a slower cut to avoid a noticable taper. THat drove the cutting cost up significantly. I'm going to look at roughing at a higher speed on the water cutter, then finishing on a lathe, but I don't think the overall will change much.

Bottom line is that I'd need to sell the kit for about $190. That would include a finished (powder coated), tapped part along with the proper fasteners. I could also do the installation if anyone prefers, but I'm sure any of you can drill out rivets as well as I can!

An additional option may be for me provide the rough hub, and let the customer do the tapping and finish work (the fastener holes are already in place - they just need tapping). I reckon this would be in the $130 neighborhood.

It's also a bit heavy. A plastic such as Delrin would be a no-brainer (and much cheaper) on the water cutter, but I'd then have to specify rivets, since I would no longer trust female threads in the spacer.

Is this making sense to anyone?