Last year i purchased a dozen dater stamps for a dollar (and with shipping it was still less than $10) on eBay. The last year on the stamp was 2005, so I had all last year to fiddle with them and find uses for them. And now the new year approaches.
I’ve purchased a single dater on eBay for around $12. It will last for six years, so that amortizes nicely. Still, i didn’t feel like replacing the one at work for $12, particularly when i have a stack of perfectly uesful ones except for the small nagging bit about not being able to stamp the year “2006.”
I also had a number of other things around.

Glue, blade, tweezers, cutting mat and a couple of the daters. Note the altered dater on the right.
My first attempt of cutting the last digit of the year into a separate strip while still mounted on the dater failed because i couldn’t wiggle the digit around without breaking the strip.
However, popping the dater apart turned out to be fairly easy. First step was pulling out the knob that turns the phrase. It took wiggling and pulling and some nudging of the date dials to make it pop out, and each time i felt like i wouldn’t be able to repeat the removal, and then suddenly it would be loose. Since the dials all rotate about this piece, i’ll call it the axle.

Exploded view, missing the two dials and two single-digit bands that make up the date of the month.
After pulling out the axle, the metal part at the printing end slips off the two forks. It’s not a correct analogy, but i’ll call that metal strip the platen.
Suddenly, i had a pile of dials and rubber strips and bits of metal.
I tried again to slice the digit part off the year band, changing 2005 to 200 and 5. (These are the crossed bands in the second picture.) I could carefully reassemble the two bands to extend the dater from 2006 to 2009. (More about reassembly later.) This seemed almost anticlimactic and like only a small win.
I thought a bit about it, wondering if there was some similar alteration to do on the phrases. My first attempt was to take the “A” from “ANSWERED,” an “L” from “CANCELLED,” and the “EN” from “ENTERED.” This was possible because each phrase is on a raised bit of rubber. I sliced off the raised bit under the letter. Using the E6000 glue and the tweezers for placement, i put the “A” and “L” in the place of the “EN” to create the phrase “ALTERED.” I also substituted two single digit date bands for the year band so the dater now marks [phrase][n][n][month][n][n]. While a little ambiguous, perhaps, particularly because i date in the ISO ordering with year first, this will allow me to date things to using years ’00 to ’99. It also allows me to date in ISO order (but still with a century “ambiguity”).
I will likely make more alterations. The “NSWE” in “ANSWERED” could be “NEWS.” I’ll keep fiddling.
Reassembly is a little awkward. I found it best to stack the dials and bands, being careful to have them all oriented correctly, then insert the axle through the first side and through all the dials — but not into the final hole. I then slipped the platen in place, pulling the axle out of alignment to give the platen a little room to wiggle. It does NOT slide up the metal side of the fork to snap in place — the platen can’t make the sharp turn to go from side to top.
Once the platen is in place the axle can be wiggled through the final hole. Just like pulling it apart, there’s some little mechanical trick. Here i think it’s pulling down (handle-ward) on the dials while trying to pop the axle through.
Voila! Very fun. Probably even more fun if i were to spend some time with an anagram server.
instructions, diy, how-to, make, altered