Today’s Daf Yomi Question:

The Gemara says that hammering out to broaden the chain around the animal’s neck is considered a ‘tikun’ (constructive change).  Tosfos (D”H Bisherischan) states that animal chains are typically worn tightly.  If so why do we consider it a ‘tikun’?

An un-pierced needle is not capable of becoming tamei, but can be moved on Shabbos.  Rashi explains the reason it is not Muktzah is because it can be used for splinter-removal.  Why is this reason not sufficient to render it a kli for tumah as well?