Was bored today so I played around with some WD EB/BB drives, trying to practice on alignment. I got cocky and started swapping heads from other WD drives with different DCM's and was noting which ones worked and which didn't. To my surprise, about half of these actually worked fine. However one pair of heads ended up touching as my head comb got bumped. I figured what the heck, I'll try and map the heads out with my DDI and see if it came back with one or both heads as being bad. Again, to my surprise, it works great! I continued to image 60GB with a pair of heads (6 total) that weren't supposed to work. What exactly is the science behind the damage that occurs when the heads touch? I have a feeling I should have played the lottery today.

Good job.
Some "promateurs" here will write that you just got lucky, but you probably
quite good and accurate with your hands. Well done.

How did you fasten the cover plate, any specific order of tightening screws?
Did you do a perfect alignment of the cover plate screws?

For my part I have found over the years that applying good pressure on the cover plate
at the "head stack screw" and tightening this screw first and the the others last
makes significance difference to success rate with these BB EB drives.

I forgot, the surfaces of contact between casing and head stack must be super cleaned,
makes big difference to success rate.

This is all applicable to the physical variables in heads swap for these drives.

Simply not all series / models have "alignment" problems.

"I forgot, the surfaces of contact between casing and head stack must be super cleaned,
makes big difference to success rate."

If the drive was not opened of course it is super clean (just like as when the drive left factory) , we assume at least you are working with clean room gear and even if not, a single fingerprint on headstack is in the micron range, so if a fingerprint is a problem even thermal dilatation from room temp to operational temp would be a BIG PROBLEM. But you wrote :

For my part I have found over the years that applying good pressure on the cover plate
at the "head stack screw" and tightening this screw first and the the others last
makes significance difference to success rate with these BB EB drives.

And then :

This is all applicable to the physical variables in heads swap for these drives.

No comment.

Oh dear, here we go again.

Anyway well done mattbrad2.

It's not magic.

Getting a bunch of drives together and experimenting on them is the best way to learn.

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You don't have to backup all of your files, just the ones you want to keep.