Hmm. Turns out that the lump of "cast iron" I had lined up for the base is actually a load of metal swarf mixed in with a plastic filler. So it's fairly dense and magnetic but no use for anything other than as a weight. This became apparent when I tried to take a first skim across the bottom surface.
Despite that disappointment, the other part of the job went well. This 4140 stuff machines beautifully. With a ground CCGT09 insert, it's possible to get swarf that is so fine it's an inhalation hazard, being more like bumfluff than steel machinings.
Managed to flash up the pillar without any outrages or grievous cockups. Setting the carriage and cross slide stops allows power feed with automatic disengagement so that the length and diameter can be controlled easily during roughing.
This is the bottom of the pillar. The larger boss locates in the base and the smaller one into the cross slide.
I used the boring bar with CCGT09 insert to do external chamfering with the machine running in reverse:
I was lucky to have a set of decent quality M16 taps and the tapping gods smiled on me by providing me with a 14mm drill. That saved a whole load of faffing about trying to cut the internal metric thread on my imperial lathe.
So it's job done on the pillar, apart from the 4 M8 holes underneath, for fixing it to the base. I'll do those later once I actually have a base to work with.
All is not (yet) lost on the base front though. I have a piece of 1/2" bright steel flat that will do the business. However, I had to shorten the 2 bosses on the base of the pillar to make up for the thinner section.
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