This is part of some correspondance to a customer who purchased a used Lathem clock, and is wondering if it is working properly:
Set the printed time, and set the face to match.  This is how:

HOW TO RESET A LATHEM TIME CLOCK

Written by Joe at Florida Time Clock, March 7, 1991

The easiest way to set it is to initially set it to an even-hour time.

Set it to the most recent hour prior to the current time.

Example:  2:30PM now, set for 200 on the typewheels

Then we will advance it to the correct time, as though the power was off.

Remove the cover, advance the face to 8,9,2pm, whatever.

There is a dial attached directly to the back of the face, either on the right

behind the 3, or on the top, behind the 12.  Find it.

Moving this sets the face only, it does not reset the printed time.

Next looking down the top of the movement see two tabs on a 45 degree pitch, about ½” x ½” each.

These are also about ¾” behind the bottom of the clock face plate, and about 2” down from the top of the movement, and directly above, almost touching the ribbon spools.  Press on either one of these, and the movement will be released.  It’s hinged at the TOP.

Holding the bottom of the clock face, tip it up until it locks in place.

The printwheel release arm sticks directly out of the movement on the left side.

Sometimes it has a red plastic sleeve on it.  It’s about 1” long.

Push it toward the back of the machine and the wheels will turn freely.

They only advance, they go clockwise.  Reading the wheels, you will see that they are in alignment directly below the “6” on the face plate.

Using a pen or pencil, push the wheels until you get the correct day or date, then the largest number is the hour.  2 is 2am, 2 is 2pm.

Then the next two columns is for minutes. 

If it is 11am Friday, you would set it for F 1100. 

It should now match the face time.

Once you get the face and numbers aligned, drop the movement back down.  Take a test stamp and check your work.  Correct if needed.

See the clutch wheel slowly turning to the right.  If you rotate THAT WHEEL, the face and printwheels will rotate together.  This is the easiest way to set the clock.

Let it run for a few hours, or a few days.  If they still match, that's really good.  If it loses time but does it together = they sti