Probably one of the most essential tools when working on classic Japanese bikes...
Available here: https://amzn.to/3s0IVXF
Every Japanese bike that I've owned has come with chewed up screws on engine cover fixings etc. The reason for this? A JIS (Japanese Industrial Standard) screw looks like a Phillips screw, identifiable only by a dot punched in next to the cross, and 80% of the time a Phillips screwdriver will do the job, however with old bikes and seized bolts the design of a Phillips screwdriver will cause it to 'cam out' of the head, and begin to chew it up.
“Even if the screwdriver wasn't straight, the bolt would still be fixed and the half asleep Japanese man would have done his job..”
The Phillips design originated from aircraft manufacturing, and was designed so that bolts couldn't be over tightened; the screwdriver would would slip out of the head before the bolt could be overly fixed.
The JIS design came shortly after in the 1930's in response to Phillips, and whilst looking similar, it's the angle of cross the differs. I once read that they were designed so that workers on the assembly line in Japan could tighten the bolts with minimum focus and attention on the job, even if the screwdriver wasn't straight, the bolt would still be fixed and the half asleep Japanese man would have done his job.
Nowadays I see a lot of posts online about chewed up heads and bolts that won't come out, and 90% of the time it's simply because the wrong tool was used.
This cheap set of tools will save you a lot of headaches and swearing, and I consider them to be one of the most essentials pieces of my tool kit.
Comments