Going to a harsher bit will not fix your problems. Once he gets hardened to that bit, you're going to have to go with something even more harsh. Instead, look at hiring a trainer to teach you how to make him more responsive to your aids.
Personally, I really dislike Tom Thumb bits, and it could be that your horse doesn't like them either. They're actually a fairly harsh bit.
If you haven't yet, go check out Smrobs' post, "will your horse listen to your bit?" - if you can't find it, let me know and I'll send it to you.
Personally, I really dislike Tom Thumb bits, and it could be that your horse doesn't like them either. They're actually a fairly harsh bit.
If you haven't yet, go check out Smrobs' post, "will your horse listen to your bit?" - if you can't find it, let me know and I'll send it to you.