starter (noob)

[jwmac]

#1. I'm new to the site so just wanted to say whats up and I'm glad to be here.

#2. My starter went bad a few months ago. Replaced it and it started right up no problems. A couple of weeks later the new starter sounded real rough when turning the ignition. I shimmed the starter and the problem went away and everything started real smoooth like. A couple weeks later same issue. I've shimmed it twice now and with the same sequence of events, good for a couple of weeks then goes bad. The mounting bolts are staying tight and it doesnt look like the tolerance is changing between the pinion shaft and the flyweel. I think the starter I bought is refirbished. Any suggestions??? Maybe im shimming it the wrong direction????

#3. Heres a couple pics of the noob's pride and joy!!