Unpacking "made on original Parker machinery"

There is a misconception among pen collectors regarding the claim that certain aftermarket pen parts were made on original Parker machinery. While the claim might be narrowly true, the use of an ex-Parker buffing wheel or drill press isn't what is called to mind. Rather, the implication is that the aftermarket parts were made in exactly the same way as the originals and to the exact same specifications. If we are talking about plastic parts, this they were not.
These parts were machined, not molded. Parker made them using automatic screw machines, which were large and very expensive programmable analog machine tools that could be configured to produce all sorts of parts. The size and cost (even used) of such machines made them utterly impractical for a small shop, along with the difficulty and expense of setting them up. They were only suitable for large-scale mass production, and nowadays have been almost entirely replaced by digitally-controlled CNC machine tools. Even if one were to gain access to an ex-Parker screw machine, it wouldn't be any different from one that had been used to make bicycle or clock parts. The machine itself wasn't what made the parts so much as its programming.