Ok, so important reading for folks in this thread:
Source: Me. I've fixed about 100 controllers over the past year.
Stick drift is caused by
wear and tear on the potentiometers that make up an analogue stick. On the inside of a potentiometer there is a section of almost "hoop" like resistive material, which when bridged can give a reading. The strength of the resistence differs at different parts of the "hoop". When you move the analogue stick, it rotates a little reader back and forth. Different positions give different readings - this is how the controller determines the "position" of the stick.
Now, what happens is that over time, as you rotate the reader back and forth, you scrape away at that resistive material. As you scrape away at it, the readings become less and less accurate and eventually you end up with drift. In some instances, this just means that your stick will appear to be "offset" by some value, and in other cases it means that you'll end up getting "jitter" on the stick.
Once the above has occurred, you will never be able to get a perfect reading again without replacing the potentiometers.
Whilst you certainly could use the calibration tool to "re-centre" and this may well "solve" or lessen the issue to some extent, it will not be a "like-new" solution. You've basically just calibrated it for faulty components which will deteriorate again, potentially faster than originally.
So is there any point to this tool?
Yes, absolutely and it's actually a god-send for people doing
physical repairs
When we do a repair we typically replace the potentiometers with a fresh set. The problem is,
the potentiometers are not made with uniform resistances. They tend to be
similar, but not identical. Just for example, say a normal pot should give a reading of between -1.0 and +1.0, well your replacement pot might be slightly more or less resistive than the old one that the controller was calibrated for, and so just doing a simple swap now means that the reading is between -1.2 and + 0.8.
(AFAIK) this is true of all the pots, even the ones used in the original manufacturing process of the controller. The difference is, Sony and Microsoft calibrate them at the point of manufacturing so that regardless of the actual resistance of the pot, one extreme will always give -1.0 and the other will always give +1.0
Up until this point, we had
no way of recalibrating the controllers - so doing a repair generally involved sticking in a random pot and hoping that it was similar enough to the original one that the calibration wasn't too off.
(Side note: there are additional mods you can install that let you "manually" calibrate the controllers to centre the readings, but these will often cause distortion in the overall range that the pot puts out. Either hitting the "limit" before full stick saturation, or meaning that you didn't reach the max value when the stick was fully saturated)
Basically, the repairs were a balancing act of getting it "close enough" that you wouldn't notice during gameplay, but a true "as new" repair was down to luck more than anything else.
Hopefully, with this tool it will mean that we can recalibrate the controllers to use any pots and don't have to worry getting lucky with the resistances!
I can't wait to try it out!