Genuine Newbie enjoying the forum

[m_c]

Retrofitting a machine isn't that bad, but it does help if you have a reasonable understanding of electrics.
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Novamill's are well built machines, but they are a bit limited in terms of work area. Especially height between the table and spindle, more so if they're fitted with a Coventry Quick Change system. A common mod is to fit a raising block between the column and base to increase height. They are a reasonably straight forward machine to retrofit, as unless they have an ATC, the electrics are pretty basic for a CNC.
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A Denford Triac, is the next size machine up from a Novamill, and is a far more capable mill, however it depends on what size of parts you'd like to machine, as to what would be more capable.
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Outwith Denfords, but staying with small mill type machines, there are a couple Chinese import options (Sieg KX machines & Syil machines). Other option is a router style machine, but to handle aluminium regularly, they have to be well built. Zapp Automation have started doing kits, or you're looking at building your own (or paying someone to build one for you).