Anthony Marchand Bicycle Repair And Maintenance information And Tips

  1. JIS Screwdrivers by Brandon Jackson and Johnny Jarvis, 2011
  2. JIS versus Phillips Head Screw Drivers from Never Stop Building, Dec. 2014
  3. Tools - Vessel JIS screwdriver by BRIAN MULLIN, The MTB Bike Lab, JANUARY 26, 2016
  4. The Screws On Your Japanese Derailer Are Not Phillips Kent's Bike Blog, Feb. 2013
  5. Home Wrench: Things you want for Christmas by David Rome from bikeradar, Nov. 2015

Best Bicycle Screwdrivers

Specifically for bikes!

By Tony Marchand
I had been using US Phillips head screwdrivers on the screws of my bicycle for years. But as time passed and I acquired new bikes, I noted I had difficulty adjusting the limiting screws and rear derailleur screws on my newer bikes. I always thought I just couldn't find the right size and those that seemed correct would destroy the screw head. Then I began reading material from auto mechanics who talked about JIS or Japanese Industrial Standard screwdrivers. Could there be a difference? Most of the components we use on bicycles are made in Japan. Is this why I couldn't find the right size Phillips head screwdriver. Well here's the straight story.

Back when everyone was trying to standardize fasteners, the Japanese were no exception. They got the standard inclined plane right, but neither country got together on the head design, so the Japanese cross-head is slightly different. The corners of the US made Phillip head screwdriver show a slightly rounded inner corner at the arrow below. The JIS (Japanese International Standard) a completely at right angles.

Best Bicycle Screw Drivers
Anthony Marchand bicycle repair and maintenance information and tips.

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Thus a US Phillips head screwdriver will not fit all the way down into a JIS screw (although the JIS works find with both). Results:
The result is that a US Phillips head screwdriver will not work on a JIS screw. Note the lack of edge contact of the Phillips head screwdriver (left) on the JIS screw as compared to the JIS screwdriver (right) on the JIS screw (right). Using a US Phillips head screwdriver on our Japanese bicycle components will lead to damage to the head of the screw.

What this means for us trying to maintain or adjust our bicycles:
JIS screwdrivers are definitely different from the standard Phillips head type, although the differences in actual performance can vary depending on the fastener in question. We have found that JIS screwdrivers can be used on either US Phillips head or JIS screws. Since most of the bicycle parts we currently use are made in Japan or Taiwan where JIS is the standard, it is only natural we should be using JIS screwdrivers to expatiate maintenance and repair and keep from destroying our bicycle components. Several JIS screw drivers are available on the market in various sizes: 1. Vessel from Amazon. 2. Park, also from Amazon. Advertised as Phillip head, these are really JIS standard (it's just most people here in the US don't know what JIS is).
Also, the JIS screw head slots have a shallower depth, preventing the taller head design of a Phillips head screwdriver to properly grip the sides of the fastener (below).
Thus a US Phillips head screwdriver will not fit all the way down into a JIS screw (although the JIS works find with both).