When I bought my Proxxon TBM 220 bench drill second-hand, the depth stop was missing. As I didn't want to buy a new one, I made one myself. Depending on the filament used (I used a Tough PLA), it is probably not quite as firm as the original depth stop, but it works well enough.
Parts required:
1x M4 x 12 screw (head diameter = 7 mm)
-> can be glued in with a little bit superglue
1x M4 screw nut
Of course, I have also uploaded my Fusion 360 files and the STEP files so that you can remix and adapt your ideas and adaptions.
If you still want to buy or look at the original parts, I will put the corresponding links below:
https://www.fluidonline.de/proxxon-28128-47-skalenzeiger-fuer-tischbohrmaschine-tbm220_10072_18387
https://www.fluidonline.de/proxxon-28128-48-klemmstueck-fuer-tischbohrmaschine-tbm220_10073_18388
The author marked this model as their own original creation.