Ahh, brilliant - I shall have a trek down to my local scrapyard to see if they've got anything in there along those lines, like a scrapped mini moto hub or something - it's not terribly likely but I can look! Thanks, adz!

I am planning to borrow the basic idea of LS4, except I'm attempting to make it have a slightly larger diameter and sharper, smaller teeth to cause more localised damage. Was debating an interchangeable tooth design, but I'm just sticking with simplicity for now till I've got my head around it! I was debating that invertible design too, but I think the problems with keeping the disc suspended around the edge are just too much hassle to warrant the effort at the minute, it's something I'm still actively designing around though to try and get that implemented.

Thanks for the insight though there with LS4's RPM, I thought it was much nearer the 5000 mark! Was aiming for about that on my machine, but if LS4 can only manage 2000 at most then I was obviously way out of the ballpark there! I'm not quite sure on the diameter yet, but I'll be making an outer shell with cutouts and then cover those up with some other kind of lighter shock absorbant metal or plastic so I can maximise the diameter of it - not sure exactly how big I'm going to have it but as large as possible is the aim for now!