This came with the Logan 12" turret lathe I bought. I can find no markings in anything, no numbers, names, nothing. It appears to a wedge type, in that the silver rod seems to be eccentric and cams the holders tight. It all appears to be very well made and finished.
It appears on some of them but not all of them. On the ones it is on, they all appear to be a lock for the finger screw height adjustment. The wing nut is actually another finger screw with makes an interference fit against the height screw.
I'm not real happy with this tool post system for a few reasons. The body of the tool post itself is too tall. When the holders are in place and approximately at the right height for the tool bit to be on center, the holder is over an inch below the top of the tool post. It is so low that the finger screws for the height adjustment don't even reach above the top of the tool post. In addition to that, it appears to me that this post and holder system was intended such that the finger screw itself wold bottom on the top of the tool post as a repeatable positioning system when changing holders, ala the Aloris and other styles.
It appears to me that the tool post itself was an attempt to make a quick change tool post of the same size as the original cross slide tool posts. But when placed on top of a compound which was added, it throws the whole thing out of whack.
Another thing I don't like is the locking system. One side of the 'dove tail' is actually round, it cams against a movable shaft which is held in place by only a wire clip on bottom and a clearance hole on a bracket on top. I don't feel great about the repeatability of the locking.
I also don't look forward to having to build more holders. In fact, rather than 'rebuild' this system, I am seriously considering building a new tool post and holders for this late.