I only have a photo of the part finished crank but this is how I made it in one piece on my Warco 240.
I roughed out the two end diameters leaving +2mm for cleaning up. Then holding the long end in collet chuck mounted in the four jaw to get the throw. I machined the centre and inside faces of the flanges to width and to the large diameter. Patience is key here. I then did the conrod dia to size.
I made two adjustable pieces to maintain the gap between the flange faces. (These were also used when profiling the flanges.) A small alloy block drilled and tapped 6mm plus a 6mm bolt and backnut to lock. I superglued this between the flanges. Put the long end in the collet chuck and centre in short end and turned short end to size. Reversed and turned long end to size.
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