could you get us a pic. of these teeth. between the bad starter/battery last time and the starter doing the same thing it may have worn the teeth on the flexplate too much to engage.
As you can see it's minimum, my bet is it is a very different and recent problem as until about 2 weeks ago it was starting fine! Hopefully hahaha But you can see the teeth starting to be worn and the metal flakes everywhere.
If the starter has never made a grinding sound then basically drive is engaged into teeth... The drive slamming into the teeth will cause wear, though sounds as if your's is a bit excessive... You could have a bad drive... It has a one way clutch and if rollers are hanging the drive could be engaging and motor running, but just freewheeling... Also there is a short nose starter that was used on '60s stick setups, those won't fully engage on automatics or late stick setups... Ahhh just saw your pict, don't worry about it most all used ones are similar...
the starter has made grinding noises when it fails on first attempt and I go again. Here's a pic of my starter, not sure if short nose or not
That's the correct long nose automatic starter, the short ones only have maybe half as much opening... If those particles are brass you have a front bearing and/or drive failure...
certainly looks like brass being all gold and all. So then the starter is def faulty. Good thing it comes with a lifetime warranty! On my way to the parts shop for an exchange! Thanks again for the help as always!!!