Dear friends: I need some information or advice. A couple of weeks ago, one of the plastic tuning knobs on my cheap Republic Miniolian broke. So far, I’ve bought two sets of replacement knobs, and neither one fit the stems on the tuning machines. Can anyone tell me what kind of tuning knobs I need to look for and, more importantly, where to find them? If worse comes to worst and I have to replace the tuning machines, what kind and where to buy? Thanks.