Phillips bits Vs. JIS Bits: What's the difference? October 06 2018
Does your Phillips driver feel like it doesn't quite fit that screw? Chances are that's because it's not a Phillips screw, it's a JIS screw.
JIS, or Japanese Industry Standard screws are just different enough in shape that Phillips drivers will not fit well and slip/strip them. The difference is in the leading angle of the point of the driver. Phillips bits have a larger angle and therefore don't bottom out in the JIS screws, causing slippage.
Where can JIS screws be found? They're holding together pretty much everything manufactured in Japan most notably Honda Goldwing & other Japanese motorcycles, Mazda Miata's and a broad range of small engines and medical and CNC equipment.
How can you spot a JIS screw? See the graphic, the vast majority of them have a tiny dot stamped into them. However, customers have wrote in and said that not every JIS screw has the stamped dot.
So if a Phillips driver doesn't fit quite right and the product is Japanese in origin, it's a safe bet that the screw is a JIS.
Our customers have left them excellent reviews. G says:
"My motorcycle's petcock decided to start leaking due to a dried out o-ring and gasket. I grabbed my Chapman kit and started the disassembly with the new bits. I double checked the fit first before selecting the best bit for the job and found the fasteners easy to remove with no slippage whatsoever. The screws removed were small and and of soft material so any slippage would have resulted in a buggered screw head. No problem, thanks to Chapman." - G