I saw this post on another forum and thought it was interesting....
"OK, maybe most of you know this already but I just learned about it recently and so there have to be at least a few folks here that are unaware...
I've always heard that Japanese screwdrivers fit Japanese screws better, but I always thought it was maybe some industrial tradition in Japan to make them all at one end of the spec or something. Turns out Japanese Phillips screws are quite different from US ones, they're made to a totally different spec (the "Japanese Industrial Standard" or JIS, where the US spec is ANSI) and the heads are even stamped with a small identifier. Next time you're at your bike, look at the screw heads. If there's a dot next to the slot, then the screw is JIS Phillips, not US Phillips. My Triumph has these things all over the place because a lot of the subassemblies are Japanese.
Here's what the dot looks like:
http://www.katun.com/images/jis1.gifEven though the screw in this picture is stripped you can still see the dot above the remains of the slot. If you come across one of these screws and it's tight, be very careful and exert a lot of pressure while removing it, as there's a good chance it will strip with a US screwdriver. Smaller screws seem to fit worse, e.g. lots of folks strip the little screws that hold float bowls on carburetors. If you google "JIS screwdrivers" you'll find a lot of angry folks on various forums that have stripped screws on model airplane engines and on old cameras.
If the situation appears risky you might want to order up a set of the correct screwdrivers. You can get a cheap set from:
Precision Screwdriver Set: Japanese Industrial Standard
or if you're a tool junkie you can get high quality from
- VESSEL Tools
The weird thing about this standard is that the big tool companies (Snap-on, etc) don't seem to make JIS screwdrivers -- which is odd in that you'd figure they'd be on all Japanese cars. The only folks that seem to make JIS screwdrivers are, well, Japanese screwdriver companies..."