here a little video about making an extrusion screw. it only outlines what’s needed, the process and the dangers.
here again in numbers/details:
metal lathe : min. 2Tons, min. 1meter cutting length capacity, min. 3Kw, 1000 Euro second hand
inverter for lathe: Omron MX2, 200 Euro, needed to add some more electronics
material: chromium, min. length 70 cm, start diameter 25/25 mm
labor – cutting time: 10 – 15 hours in total
optional : angel grinder to take off most material (safes 2 hours lathe time)
cutters: HSS blanks, min. 2x2x10cm
output quality : near perfect but compared to industrial screws rather middle
required skill-set : medium – advanced
danger : high, but can be limited with ‘limit switches’
others: grinding papers ( 80/120 grid), some files to make better edges