Most Japanese made motorcycles cars, and equipment uses Japanese industrial standard (JIS) screws. If I were to work with a JIS screw and use a JIS screwdriver, it would fit perfectly and would not cam-out. A Phillips screwdriver would cam-out after a certain amount of torque when used on a Phillips screw. When you compare a JIS screwdrivers tip to a Phillips screwdrivers tip you will notice that there is a slight difference.
Common mistake:
The Phillips screwdriver is designed to cam-out when torqued to a certain amount. Since a Phillips screwdriver does not fully seat inside a JIS fastener it will cam-out and result in stripping off the JIS fastener head. Many people say that Japanese manufactures use soft metals for their screws but this is far from the truth. Using the correct screwdriver (a JIS screwdriver in this case) will not strip the head of your screw.
Japanese Industrial Standard characteristics:
The Phillips screwdriver has a tapered flange designed to cam out the screw head while the JIS screwdriver has a straighter flange edge that resists it to cam out. A JIS fastener does not have the same shape as a Phillips fastener even though they look similar. The JIS fastener has sharp corners in the center while a Phillips fastener has beveled corners. This is why a Phillips screwdriver never fully sits in a JIS fastener. To identify a JIS fastener you can tell by a single dot or an “X” to one side of the cross slot like the image below.
Phillips characteristics:
The Phillips screw was designed to improve efficiency in assemblies that used power tools by helping the operator self-center with their power tool, which was difficult when using slotted screws. It also increased cam-out potential and less damage to drivers and fasteners. Prior to the Phillips screw design, Slotted screws were common fasteners.
The Phillips bits are sized from 0000, 000, 00, 0, 1, 2, 3, 4 (smallest to largest). The tip of the Phillips screwdriver has a tapered section while the JIS does not have this feature.
Summary:
If you are working on any vehicle or equipment that uses Japanese industrial standard screws, buying the correct tool is worth the investment. You do not want to run into stripping fastener screw heads and even wearing out your other screwdrivers. You can find a set of 3 (#1, #2, #3) Japanese Industrial Standard screwdrivers here
