Never, and as far as I know, it's cheaper to buy 10 new hard drives than to just retrieve your data from one broken (prices around $3000 are not uncommon). You need an extremely expensive "clean room" to operate on hard drives and building such room costs from million dollars and up.

In your case the problem is most likely caused by damaged media, and that is (as far as I know) incurable. If dust particles did somehov get inside, the damage will increase exponentially until the media and heads are totally destroyed.

You can only buy a new one.

But better still, bring your PC into service center. Let professionals check it.