That uses a planetary gear, and if I recall it has a single bearing on the drive. Its a neat idea, but probably a little under built. I want something I can abuse for 5-10,000 hours before a tear down.
Naw. I was thinking 3 pairs of spindle quality bearings on 3 shafts with 2 3:1 cog belt pulleys to get about 6:1 speed increase with an er collet chuck in the last set. The main and intermediate don't have to be able to spin as fast as the final set so they can be more robust. Only reason I have not started already is I would like the final drive to be concentric with the main drive, and I have not figured out a simple elegant way to accomplish that yet. Hmmm.... I think I might have just figured it out.
I would probably just buy a speeder on ebay, but they all have CAT shanks. I need a robust straight shank or a KWIK 200 (or RS200) shank.
Been there and done that, Bob.
You might have your calcs wrong though, because 3x3=9 times speed increase, if you're doing it the way I think you are.
I'm pretty sure you'll come across many problems doing it that way, because I know I did. As soon as you start gearing things up, you run into problems with frictional losses being multiplied. By using belts, more energy losses are incurred due to their continual flexing.
I mean, you're at a six times (torque) disadvantage purely due to the gearing effect, add in the belt and other frictional losses such as grease lubrication etc and that might bump the disadvantage to ten times - maybe more, who knows? And definitely no lip type oil seals!
The first bearing-set after the main spindle also has to be without play, run concentrically so the whole assembly doesn't wobble, as well as be able to resist the cutting forces - all with minimal friction.
It's how I came to the design I showed earlier - simple and free running.