[cypher]

Welcome to HC & well done for giving this little guy a good home.

It can be hard to fathom just why they chew the bars sometimes, it can be stress, boredom, attention seeking (especially if it results in being let out!) or sometimes just because they can. You can't always figure out a definitive answer tbh.
If you have a photo of your cage set up we might be able to come up with ideas that could help.
I wouldn't use mineral chews as they aren't generally good for them & a lot of hams aren't interested in wooden chews or chew toys, if you can get them try him with a whimzee dog chew (little toothbrush is best) most hams love those.
Do you scatter feed or use a bowl? Scatter feeding & or hiding food & treats around the cage for them to forage for is a good distraction.
You can also try threading cardboard through the bars so he can chew on that.
If you possibly can try not to respond to the bar chewing but get him out when he stops or isn't doing it as otherwise you can just end up encouraging the behaviour.
Hope some of that might help.