Tom Deering, 1/1998
(I presented the following findings at a New York City Newton User's Group meeting, held in the Apple Marketing Center in Manhattan in late 1997.)
About one month ago, I noticed that my Newton stylus seemed to have something stuck on it. When I wrote at a certain angle, it seemed to stick just a bit. A few days later, I got my first screen scratch. I used a clinical microscope to examine the stylus, and found what looked like a tiny glass fragment embedded on the tip. This fragment was utterly undetectable to the naked eye.
I removed and discarded the original black tip (A). I replaced it with the tip from a Wacom pen (D). The fit wasn't exactly right, so I put a piece of shrink tubing on it first, and used a pair of needle-nosed pliers to screw it into the stylus (C).
Original and Replacement Stylus Tips
Notice that the Wacom stylus tip (D) does NOT have threads, although the aluminum stylus does. The tip is held in with friction.
Incidentally, the Wacom tip has the advantage of being white, which makes it easier to see microscopic debris that may become embedded in it.
The following day, I again noticed that my stylus seemed to have something stuck on it. I popped it into my microscope and found a bit of grit on this new stylus. Here is a snapshot of this piece of grit. Magnified, the grit looks like a pink stone.
Bit of Grit (center) and a Sharp Needle Tip (above)
The bullet-shaped pointer at the top of the image is the point of an ordinary safety pin. Although the pin looks blunt under magnification, it was actually very sharp. This gives you an idea of how small the grit was. The grit was impossible to see with the naked eye. I cleaned the tip with rubbing alcohol before taking these pictures, so the grit you see is embedded into the plastic of the stylus tip. I must have dropped the stylus, and a microscopic bit of grit became stuck in the soft plastic.
Enlargement of Grit on White Stylus Tip
I am very careful to keep the stylus in the silo when I'm not writing. I also keep a handful of alcohol wipes in my bag, and clean my screen often. (Squeeze out the extra alcohol first.) So my screen is usually squeeky clean. But like everyone, I do drop my stylus from time to time.
Conclusion: Some people believe that the stylus tips are too hard, and that the plastic scratches the screen. This seems unlikely. It seems more probable that the stylus gets a bit of grit becomes embedded in the tip somehow. It's easy to drop your stylus from time to time. Softer stylus plastic would make the problem worse, not better.
In the end, I think this shows how important it is to keep the stylus itself clean, and to avoid dropping it.