All I can say is NOT A CHANCE!!!!!
First, I’d suggest you double check the max (no load) rpm on your router. Most routers operate at a much higher rpm than you noted. Good variable speed routers usually only have a range between 10,000 – 25,000 rpm, and cheap routers like my Black & Decker run at 30,000 rpm to make up for lack of horsepower.
As noted by others given the weight of a sanding drum setup at router spindle speeds you’re going to generate some significant centrifugal forces. The balance of the drum you intend to use had better be spot on perfect. Any imbalance in the mandrel or materials and it’s only a matter of time before it comes apart. It’s late, so you can do the math on how fast those pieces of abrasive, rubber, and possibly steel will be traveling.
My take on the idea is not to try it.
I understand the impulse for people to improvise. There are some truly ingenious improvised tools and fixtures created by many members on this forum. However, remember Murphy’s Law? Well, Murphy is alive, well, and standing right next to you when working on a blade and he’s looking for a chance to ruin your day. If there’s machinery, sharp edges and flames involved, ol’ Murphy is sure to be close by and grinning.
