Personaly looking at the case construction I would save my penny's and use this as a learning tool and if you really want a good 1680 then find an mbw or wait until HH has his case sets ready rather than spend money on what will be in the end (I you want a good modded 1680) something you wi never be truly happy with.
this one
http://www.ebay.co.uk/itm/3mm-x-0-35-Metric-Taper-and-Plug-Tap-M3-x-35mm-Pitch-/150672852218?pt=UK_BOI_Metalworking_Milling_Welding_Metalworking_Supplies_ET&hash=item2314cd44fa
We did to start but then we experimented a little and the best bit was an apple pasty and vanila icecream at the end,
I have not made pastry since i was 11 yr old at school, came out quite well