Hi Marcus,

Welcome to the forum.

Unfortunately the TL;DR is exactly what hanermo2 says - BUT, don't be discouraged, just you need to keep exploring DIY builds to get a realistic grasp of the limitations.

Start here: http://www.mycncuk.com/forums/253-DIY-Router-Build-Logs

Look for the popular threads with lots of pages and responses, grab a few beers and a blanket, settle down for the long read. You'll pick up an awful lot. Unfortunately so many people just can't be bothered to do this step before jumping ahead. All your questions above will be answered, and more.

The classic Dunning-Kruger peak is "I want a machine that can cut aluminium and steel well, but also have a massive build area for wood and I don't want to spend much money". Show me a commercial machine that can achieve those aims for less than £500k and I'll be impressed - that should be a good hint :)