I've been a lurker and thought I'd finally say hi and see if I can get some local advice.
I have been dreaming of a cnc mill for some time. I'm just hobby driven and really only want cnc to cut some curves and more complex shapes. I have some lathe and milling machine experience and I'm quite comfortable counting out distances on hand wheels. most of my experience is on a knee mill which is just so versatile and solid.
I'd buy a second hand knee mill in a flash if I could find one locally (or close by in se QLD) but normally price and freight stop me. from what I have seen a cnc conversion can be successful but it would cost more due to the larger ball screws and servos/steppers needed.
I have considered taking the plunge on a cheep syil Cnc machine, but as soon as I start thinking about y - movements over 200mm the price seems too much for a hobby machine. after all it will sit round doing nothing for most of its life and $10K can buy me a lot of machining at a local cnc shop. even the smallest machine seems excessively priced.
the other option is a small bench top machine for conversion. it doesn't have the movement I want, and poor finish/ light machining and is likely.
I spotted this one
Quantum Geared Head Mini Milling Mill Machine - Drilling Drill Press | eBay
the column looks light, so rigidity would be low. movement is good for a mill that size. and the screw locations look convenient for CNC conversion.
the plan would be to buy a 3-4 axis kit from ocean controls and source some ball screws.
for most of my stuff it would be ok (I only do light work in aluminium). however I would love to be able to profile some 20mm aluminium plates and a want advice if what I'm dreaming up is possible for CNC?
I would like to cut curved plates, like a rounded star shape or multiple cams around a circumference. the plate would be 220mm at the tips, so on a little mill the Y axis is too small.
can I use a rotary table with x and y movement to profile a plate? if they can work together then you would only need 110mm offset on the rotary table and minor y movement to cut the curves.
am I dreaming or is this feasible? I would expect I would get probably 0.2mm steps in the machining but I can live with that for the convenience of prototyping these plated at home.