Hole closing punches on something so small can be tricky - I found out the hard way how soft some roller are. If only slightly loose I use Loctite. Not ideal, but does the job neatly and can always be removed.

07-05-2025 - I will be rebooting the server in order to apply new security and software updates. Please do not be alarmed 🙂 it should not take more than a few minutes.

Gluing or shellacing the roller in place should be discouraged as bad practice as, whilst it helps in the short term and gets the job done, it then becomes and issue for the next repairer down the line, or even worse, it becomes loose and negates the repair prematurely. The most effective and professional repair would be to cut a new balance staff. The other effective repair requires a special tool as mentioned by @Neverenoughwatches - however, those tools are extremely pricey, and would rarely be used, and so hard to justify the expense. If it is extremely loose (falls off with gravity) then it needs to be replaced, or a new balance staff cut. If its loose but holds still with gravity then I would be tempted to close the hole slightly with a hole closing punch on the staking set - quite risky but better than gluing.

Richard and Andy both make very important observations, so let's take a step back and see what we are dealing with. Does the crown tube in the case have a thread on it? How did you remove the stem? Do you have a photo of the movement in the case? You might be able to remove the female part of the split stem and reuse the existing crown. Can you see a thread? There are one-piece stems available for the 2472 for reasonable prices. The split stems I found on ebay for the 2472 are a little more expensive, but have the male and female parts the opposite way round.

Welcome aboard.  Your local watch repair shop might know how to fix it.