Newbie looking to buy mill/CNC but which one?

[halcyon0]

Hi all. I would like to start some machining to make computer cooling blocks and
motorcycle/truck parts. I know nothing of CNC or milling. Should I get a manual
mill vs CNC? How hard is it to learn to CNC? Can I convert a manual mill to CNC
later? The mills I am thinking about purchasing are Taig, Lathemaster, Homier, Maxnc, or the Sieg X3. Are the Sieg mills the same as the ones that Harbor Frieght sells? They look very similar. I plan to be working with primarily aluminum, but may dabble in copper and stainless steel. Any recomendations?

Thanks in advance!

Charles

[Al_The_Man]

As a rough guide, if you are doing one-off items then probabally a manual mill would be OK if you plan to do production of any considerable quantity then the CNC will shine.
If it is something that you intend making a buisiness out of, if only part time at first, and you have the room, go for the largest mill you can afford, especially if you want to machine stainless e.g. minimum 36"x12" table Bridgeport knee mill etc.
There is a lot of work converting a manual mill to CNC, machined pre-loaded ball screws alone cost a bundle, I would not reccomend going with rolled BS with no preload. There a lot of small CNC mills that come up on ebay etc and usually it is alot cheaper to bring those up to snuff than starting from scratch.
Al

[Noah]

Al, do you really think he needs a table and mill that big for machining stainless? I understand if he is gonna make a large very complex part or something, but even micro sherline mills claim to be capable of machining stainless so long as it is small. I would determine what your size limitations are before even worrying about quality. If you need to machine a 20 x 10" plate, Al is right you will need a good sized knee mill, but a mill of this size will probably already have awesome accuracy. If it turns out you can go smaller, then start deciding what accuracy you need.