Operation of the toolpost is as follows.
1. Unlock by breaking the lever free in the counter clockwise direction to unlock toolpost.  Continuing to move the lever counterclockwise will move the tool post counterclockwise to the next tool position.
2. When the next tool is in position, and the toolpost is manually rotated clockwise to make sure it is against the positive stop.  Rotate lever clockwise to lock the post in the new tool positon.

See the video of the tool post being indexed.

Reassembly of the toolpost for proper operation.

1. Mount the center post sleeve on the center stud making sure the pin in the t-nut base is located in the slot on the bottom of the center post sleeve.  See picture 69A.  It is critical that the center post sleeve cannot rotate during the entire assembly process.  In other words the pin is always engaged in the pin slot.  During the assembly of the lever on the center post sleeve the sleeve may have a tendency to raise up above the pin allowing the center post sleeve to rotate.  A reference mark on the top of the center post sleeve will help determine if the pin is in the pin slot during assembly.
2. Place 4 sided tool post over center post sleeve.  Again make sure the pin is in the center post sleeve pin slot which will not allow the center post sleeve to move.  See picture 72.
3. Insert indexing stop pin (pic 70, 71, 73, 74) into base of tool post making sure the angled portion is correctly oriented to the index slot in the center post sleeve (see pic 70, 73, 74).  Insert spring and socket set screw.
4. Carefully thread lever onto center post sleeve (again make certain center post sleeve does not lift off of the pin allowing it to rotate).  There is a pin in the bottom of the lever that will fit into any of the 3 pin holes (120 degrees apart) in the top plate of the toolpost which will provide the index of the toolpost in the counterclockwise direction.  Continue to thread the lever until the lever is close to touching the top plate but not to the point it pulls the center sleeve up freeing the pin from the pin slot in the bottom of the center post sleeve.
5. Place the spacer/washer on the center stud and tighten (don’t overtighten).