2 of my old hobbies come to mind when looking at the construction of this spindle: RC Cars, Skateboarding. I'd consider it a good buy because the brushes can be replaced, bearings likewise can take extreme abuse (ceramic withstand up to 100K RPM) and the construction looks relatively sound. Nice lathe work and great feedback. Sorry, I dont own one but have looked at spindle he has for sale in past and liked the craftsmanship.
This should be signifigantly quieter than Bosch or router spindles.
First of all I know little about that quality of spindle, however, the ad is pretty straight forward without any obvious 'exaggerated' claims, and seems to show that he has pride in his workmanship...
His feedback shows 275 with 100% positive, a good sign, and total feedback is 434 at this time, which to me means quite a few happy repeat customers, and that's an excellent sign...
When I say I know little about 'that quality' of spindle, I mean that I have made a few [for myself] out of mild steel and standard [read cheap chinese] bearings, and scrap parts from the local metal recycler, but nothing near approaching what he has listed...it's closer to art than hardware... sigh..
I have 2 of these. Build quality is good. Bearings are a bit iffy. They do not look that great when taken apart. The chuck asssembly will slip the bit upwards under higher step-down load. Even fully tightened it will slip upwards, they could really use a thrust bearing at the top. TIR is low as specified. The O-ring drive belt cannot handle too much load and should be replaced with real high-speed v-belt.
They would make good engraving spindles but not really useful for cutting.