Desktop CNC routers and tool life?

I have a CNC router that is just a small desktop model.

I originally purchased this unit to make some special tools I had self-designed for working on hard drive cavities.

The unit uses a Ryobi SS50 single-speed rotary tool as a "router" and Xylotex controller, driven by Mach3.

I've used it to cut a little BB plywood and MDF, but my feed rates have to be pretty low due to the underpowered spindle, and I also think my steppers are inadequate.

So this leads to shortened tool life, I'd guess. My spiral router bits turn dark pretty quickly.

OTOH, my wood doesn't burn and it seems to cut alright.

Anyway, any tips for very small desktop CNC users? I imagine the problems I face are similar to others with very small CNC routers with underpowered spindles.

There was a lengthy discussion on that on the ShapeOko forums. Consensus here:

http://www.shapeoko.com/wiki/index.p...utting_Formula