Starter eaten

[DobbM]

👋 I just had my starter motor rebuilt. Ran it daily for about three weeks and today -- a nasty sound while cranking it. I look below and I see these three bits laying on the garage floor. I remove the starter, and yup. Problem identified.
My question: how did these three shard end up on the floor? The starter was fully attached. Is there a natural way that they could have got thrown free? Or should I worry more? Thanks.

  

[Bob Preston]

Gravity. 

[ronmanfredi]

If your car is like my 63 with an auto trans, the bell housing isn't completely sealed at the bottom and those pieces could drop through the gaps to the floor.

[mfg]

Probably through the 1” (?) hole provided to drain converter…. But more importantly ‘Why did this happen’?

[DobbM]

Why is a great question. Inferior metal? Bad batch?

[DobbM]

It happened again. Same exact issue. Car ran fine for 3 weeks, then, bam. The engine turns over just fine. Doesn't sound labored or anything. I'd question my own installation, but it doesn't seem too difficult, and I'd question myself if it happened on the first cranks. 

Any suggestions? Obviously I won't be going to the same shop. Ugh.

[Gunslinger]

Starters sometimes require shims to be lined up for proper engagement.  That may be the problem.