Most people don’t know that there are multiple screw types that look like the traditional Phillips.
The most popular of which is the JIS (Japanese industrial standard), to which the JIS screwdriver is made to the JIS B 4633 specification.
The other is a pozidrive, but those are more commonly understood to be different.
Phillips screws by design were created to cam-out; a process in which the driver is meant to jump out of the screw when a certain torque was reached. There are many theories to why, such as dangers of over tightening on airplanes, or tool longevity, but never the less at one time or another everyone will experience a Phillips round-out as a function of its cam-out design.
Both JIS and Pozidrive are re-engineered standards that aim to reduce or eliminate cam-out. From this point I will focus on JIS vs Phillips.
Even though the JIS and Phillips looks extremely similar, they are two different designs and the drivers are not meant to be interchangeable. Using one in the other will lead to frustration and a rounded out screws.
JIS screws are most often identified by a dimple or an X on the screw head:
However it does happen that a screw may be a JIS but may not be indicated by a dimple or marking.
Therefore always assume that a screw is JIS if it has a dimple, but not the other way around. If the screw that you are looking at doesnt have a dimple, is it likely that it was Made in Japan? If not, it is safe to assume it is not JIS.
So you’re thinking, great, i’ll just get myself a JIS screw driver for those JIS screws. Well, here is where it gets complicated.
There are the real JIS and the not-so-real JIS screwdrivers. Remember, JIS is a standard, so a screwdriver needs to be made to that exact standard to be considered authentically JIS.
Most JIS advertised screwdrivers sold today by companies like Vessel, Hozan, and others are actually conforming to a new standard: DIN 5260 which is identical (at the tip) to the newer ISO 8764-1.
But wait, DIN stands for Deutsches Institut für Normung e.V. (German Institute for Standardization), and ISO is the International Organization for Standardization. Neither sound very Japanese, do they?
The reason these companies have changed to DIN 5260/ISO 8764-1 is because the new standard is designed to work in both Phillips and JIS screws. For the most part that is true, it does work on both screw types, but like anything meant to work with multiple things, the middle ground means compromise. The JIS standard screwdriver will always outperform a DIN/ISO screw driver in the worst of conditions on a JIS screw, and the same is true in reverse.
As you can see, the JIS and ISO standards are very close, but not exactly the same:
If you only need one set of screw drivers, or are an infrequent user, the new DIN/ISO standard screw drivers will likely work for you, but if using the right tool for the job is important to you or if you frequently work with Japanese or JIS screws, consider investing in proper JIS screw drivers that are built to JIS B 4633.
To date, I have only been able to find one confirmed manufacturer that still uses and builds to JIS B 4633, and that is SUNFLAG otherwise known as New Turtle in Japan:
“<< Both 888 and 215-P are produced in our factory in accordance with same JIS standard [JIS B 4633]. >>
<< One shank is round and the other is square. So, finish of the production naturally looks different. Depth and width of the each recess are different because shape of shank is different. The important thing is angle of recess. If it’s different, it cannot be fitted with #3 screw. Please insert each screwdrivers to #3 screw so that you can find that points of each screwdrivers fits to screw in the same way or feeling. Thank you for your kind attention. B.rgds H. Shimizu of SUNFLAG Japan. >>