10/05/2011, 10:29 PM
or, a possible alternate title: My Touchstones work better than yours! neener neener neener!
The back of the Pre3 is shaped very differently than previous Palm phones. Stock Touchstones just barely hold the phone in place, because the phone sits 'high-centered' so the magnets in the touchstones don't get very close to the metal inserts in the phone's back; this also allows it to rock side to side adding to the trouble.
The solution? Reshape the surface of the touchstone to better accomodate the Pre 3's back, so that it makes better contact with the magnets and sits without rocking. Horizontally, the shape of the touchstone is ok, but vertically it's too concave. The Pre 3's back is almost flat in the vertical dimension.
There are no doubt many ways to accomplish the re-shaping, some of which are more elegant or prettier than what I did. I just took a half-round file and ran it vertically across the 'palm' logo, though because of the concavity only the areas above and below the logo actually got filed. My Pre 3 now locks in just as well as my Pre+ always did, and sits solidly without rocking.
(edit: I should mention that the flash used to take the photo (pre 3) really makes the filed areas stand out glaringly... which is good for showing you what was done, but might scare you to think it will make your touchstone an eyesore. under normal light, the filed areas just look a little grey, but don't really stand out so bad. the filed areas could be dressed with fine-grit sand-paper (start at 400, finish with 600 or even 800) to make them look nicer.)