Mike

The two screws (LA8) lock the gib to the apron casting and have to be slacked off to allow adjustment of the gib, once adjusted they are tightened up to lock the gib in position.

I have had the carriage off my lathe many times and the way I adjust it is before putting the apron back on I slack off the two screws LA8 and adjust the gib so that the half nuts move easily with no play when opened and closed with the lever, tighten the screws LA8, hold the apron up to the saddle and put in the 4 screws (LA49) in the  the saddle to hold the apron on but don`t do them up, leave them loose so the apron can still be move a bit ( the holes in the saddle are over size to allow this) , re-install the lead screw, position the carriage as far to the right as possible, then engage the half nuts and with them engaged solidly on the lead screw tighten up the 4 screws holding the apron to the saddle. This ensures that when the half nuts are engaged with the lead screw the lead screw is not bent out of alignment. As far as the adjustment of LA6, what I do is with the half nuts closed on the lead screw just to screw it in till it just stops by feel. That`s always seemed to work.

Just a note, by far the easiest way to remove the apron and saddle is to first remove the lead screw by removing the two screws and two dowels in the bracket at the right hand end of the lead screw and withdrawing it totally out of the apron to the right.

John

Edited By John Purdy on 27/03/2019 17:36:19

LA58 should be tight. It holds the clasp nut cylinder in place, but the shaft is itself eccentric to allow the centering of the clasp nut on the leadscrew.

When engaging the clasp nut the leadscrew should NOT move in the vertical plane. If the leadscrew moves in the horizontal plane, the apron securing bolts are wrongly placed.