How to replace the stamp platen in a Lathem 2121 metal punch clock:
This is the Lathem ribbon and stamp platen. At this time, you may as well replace the old motor before it fails.
First, remove the printer. That's a job, but you can do it. Use a flat bladed screwdriver.
Don't lose the "C" clip. Toss the washer if there is one.
Then, remove the ribbon. Be sure not to lose the little spring clips. If you do, fashion one with a paperclip.
Next, remove the stainless steel card plate. That takes a #2 Phillips screwdriver. Magnetized is best - with all the screwdrivers.
Cool. Now you see it. That crumbling piece of rubber. Dig it out with a small flat-bladed screwdriver. You can leave the particles in the machine, it affects nothing.
Mechanic's tip: Do NOT remove the plunger. Work with it in-place. We can do that, you can't, you will have a hard time putting it back together. You are doing dental work, without the formal training.
Do your best, clean it out, leave nothing in that area. Now press the new one in. No glue needed. The leading edge shoud be flush with the end of the inside edge of the U shaped groove.
You'll understand when you see it. No glue needed.
Reassemble and test. If it doesn't print, you've positioned the platen too far forward or backward. Tell your friends. Not as cool as saving a puppys life, but still an accomplishment. Your time might be billable at $1,000 per hour, but somehow, this seems like a good investment.