These are new Tecalemit-type grease nipples for bicycle bottom-brackets, headsets and hub-centres. They are newly manufactured in the
They are often referred to as being 2BA, but they were always 3/16 x 32tpi BSF (see photo from 1939 Brown Brother catalogue). 2BA has a very slightly smaller o.d. and a tpi of 31.35 but as a thread-form there have been some 2BA nipples around which is why they are often (erroneously) quoted. Generally most 2BA nipples that you’ll find will have the wrong head format to them.
The hex is ¼” across flats and is made from specially commissioned hex-bar.
If you want the finishing touch for your vintage cycle frame or components you’ve just found that touch!