[djh82uk]

Ive used 8mm Endmills on Steel, Ali, Brass and wood on my Taig, but then I don't have the original spindle, so can't comment on how it would hold up, but the machine itself had no problems going through 4mm thick steel but in small increments obviously

DJH

[Astroguy]

I have used 1/4" end mills on stainless steel with mine.

[Stepper Monkey]

You can also use up to 1/2" mills with the use of an endmill holder that goes on the spindles external threads (replaces the collet nut). Quite useful to be able to use the 1/2" mills for some things, though there is obviously little chance you will have much luck pushing one of that size through any tough materials. 3/8" and 1/4" works fine for those though.

[metalbyter]

I have been using tool holders made from the Taig blank arbors.
The 3/4" end mill will cut plastics as fast as you could ever want,
aluminum at slow to moderate feeds but I usually use it for surfacing.
My favorite tool is a 1/4" 3 flute carbide running at 10000 RPM in aluminum
That is where this mill really shines.
Metal_byter
http://microtools.ca