Hi,
cutting stainless and steel requires a slow speed spindle, say 3000 rpm for a 1/2 inch endmill, but high torque, probably better than 10Nm.
Most spindles sold to hobbyists are high speed low torque asynchronous motors driven by a VFD, typically 24000 rpm, way too fast for use in steel.
They work well but are not well suited to stainless/steel.
Having only 110V is going to make your search even tougher.
May I suggest that you look at some of the commercially available drill-mills, of which this RongFu45 is typical:
https://rongfu.com/mill-drill-machin...-machine-rf45/
They are rigid enough (just) to do OK in steel and stainless. Anything less rigid will just not work, it will flex and vibrate like hell.
Clearpath are good quality and made to be easy to use for first time servo buyers but they are expensive for their power output. Research Delta (Taiwanese brand made in China) or DMM (CanadianI'm looking at clear path servos for the motion control
brand made in China). Both are good quality with vastly better encoders, good support, documentation and most importantly free set-up and tuning software, at fair prices. Do not be taken in
by Clearpaths repeated marketing strategy of claiming maximum or peak power/torque outputs.......look instead at the continuous or rated power. This is the far more useful
and realistic spec.
Craig