Picador "tailstock" Plummer Block, marked "Fig 221" The centre height is approx 3.75"
This is the same format as a standard (fig 220) tall-boy plummer block (as shown here:
formatting link
but with a central shaft that is extended/retracted about 1/2" by a large handwheel. The central shaft is externally and internally threaded; a threaded "centre" screws into the internal thread and can be locked in position.Apologies for the poor description, I haven't seen one of these before. Please ask if you need more info.
Item 160259973696
Dave