The only known surviving Dalton Lever-action Collet closer now fitted to Dennis Turks superbly restored Lot 5  lathe.
Dennis writes:
If you look at the first picture and behind the closer, you will see that a link going from the handle to a cast arm on the back of the machine. Through the link is a screw, standing proud, that fits into a special casting that also forms the lower door hinge - this fitting being the first item that identifies a lathe supplied with a lever-action collet closer of the factory-installed type. The second identifying part is the upper gear guard, this having two pins to  hold the closer guard, while the third clue (and this cannot be seen in the photographs)  is a special gear on the end of the spindle. Most Dalton lathes have an end-of-spindle gear about 7/16" wide (it drives the tumbler gears) but, on lathes with a factory collet closer the gear is extended to become about 1.25" long with a cut-out at one end and the rest of the gear extending almost to the outside of the upper gear guard. This special gear has a pocket inside that the closer plugs into - it's a very snug fit and the closer has to be tapped into place.  So, there are three things that identify a lever closer lathe. I also have a Dalton 9 with the special door hinge casting with the arm to hold the end of the collet closer. It also has the special gear and the special upper gear guard but the lathe was equipped with a shop-made hand-wheel closer when I got it and for a long time I did not know what the three different parts were for - but figured it had to be something to do with a lever collet closer.
Incidentally, none of these three items are shown in any of the catalogs we have just the closer itself. On the Dalton 9 4C collets are used, so there is a 1 inch hole through the spindle for the much larger draw tube compared to the Lot 5's 3C set-up. I have never seen a Dalton Lot 6 or Dalton 9 lever-action collet closer but I would imagine it looks just like the one in the pictures - but almost certainly somewhat larger. To my knowledge a Lot 6 has never been found with fittings for a lever closer,  but we know they were made.