There is a lot of good advice in the previous post.There is also one piece I would disagree with,namely going to floor level with the machine.You will probably spend more time cutting sheet material than 3D machining and inevitably there will be a lot of tool changing and sheet positioning.You will get much less back ache and your knees will suffer less if the machine is set to a normal bench height.When you have a large or heavy item to place on the machine,it is a gret deal easier with one of these:




Not hugely expensive and also helpful when you need to lift the finished item into a van for delivery.The topic of machining tall workpieces is something to consider very carefully and I noticed the reference to the spindle itself being an obstruction,please consider this very carefully as a good number of novices seem to believe that building a machine with a large Z range means they will be able to machine anything that fits beneath the gantry.Not only does the body of the spindle represent an intrusion,the backplate on which it is mounted is also likely to have corners that could dig into the job.For taller and more complex work the 5 axis machine is the only way to go but obviously the complication and expense will increase by a lot.So too will the difficulty of finding a 5 axis CAM system with a good post processor.