Step 10: JIS - Japanese Industrial Standard

Picture of JIS - Japanese Industrial Standard
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Often improperly referred to as Japanese Phillips. Commonly found in Japanese equipment. JIS looks much like a Phillips screw (and even more similar to Frearson), but is designed not to cam out and will, therefore, be damaged by a Phillips screwdriver if it is too tight. Heads are usually identifiable by a single raised dot to one side of the cross slot. JIS B 1012:1985 screw standard is throughout the Asia market and Japanese imports. The driver has a 57 degree point with a flat tip, parallel wings.

Advantages and Disadvantages of JIS

Most people and companies outside of Japan have absolutely no idea what they are. With the similarity in appearance to the Frearson and the Phillips the screws are often damaged in removing and installing with the wrong tools. JIS tends not to camout like Philips. The JIS driver can be used on Phillips quite easily but not reciprically. Drivers are not easily available in North America, try your local RC Airplane hobby shop. Most RC Helicopters use JIS screws to mount the propeller. JIS-spec cross-head screws are generally marked with a single raised dot or an "X". JIS always fit Phillip fasteners, but because of slight design differences, Phillips drivers may not fit JIS fasteners. (unless the tip is ground down a bit).
farve3 years ago
Hello, I am doubting what kind of screws has a MacBook Pro.
(I wrote a post at iFixit)

See this photo (big, more here) : http://guide-images.ifixit.net/igi/D3MMQfb6G3HMrtNk
They don't seem Phillips, may be JIS or Frearson.

What do you think?

TA-1254 years ago
Good morning, ArcticPenguin;

From your posting on 2010 February 11:

"I'm almost sure what you refer to as Eiki ISO screws were actually JIS-Type screws with ISO metric threads. Two ways of saying the same thing basically. Similar to if I'd call them Yuyama ISO screws."

From a fading memory, I think your statement is correct.

In about 1965 or thereabouts, the movement toward some standardization in metric fasteners was well under way, and the JIS (Japanese Industrial Standards) people were beginning to align themselves with most of the rest of the world in making fasteners that would be interchangeable with the same thread specifications. The DIN standards seem to be the ones that were most favored and were adopted as the ISO standards. As you mentioned, the main shift in the JIS screws was in the change from the previous JIS thread diameter and thread pitch to the now standard ISO specifications. This affected the smaller size fasteners the most, as far as the JIS screws were concerned. The more common sizes of 6 - 1.00, 8 - 1.25, and some others, were not affected.

One of the differences was in the 5mm diameter screw where the previous JIS Standard of 5mm diameter and 0.75mm thread pitch became the same as the DIN or ISO 5mm diameter and 0.8mm thread pitch.

This is where the distinction becomes important. At this point, to distinguish between the earlier JIS Thread Specification and the newer ISO Thread Specification, they added to the head of the fastener, or the side of the nut, the "dot" or "dimple" or small round recess to show that this is the new fastener, and not the older JIS Thread Specification. The form of the head of the fastener did not change; it is still the JIS head using the JIS tooling for installation and removal. Only the thread form or thread specification changed. This is the significance of the "dimple" on the head of the JIS fastener.

Gecik6 years ago
In the 1970s and early 80s -- back when "movies" were strips of photographic film I repaired those movie projectors. Eiki was a Japanese company with very good, easily maintained 16mm projectors used extensively at colleges and universities (at least in the USA). Eiki projectors used what they called "ISO screws" and which sound very much like your JIS description. The ISO screws were difficult to remove with a Philips screwdriver, but were a breeze with the ISO screwdrivers supplied by Eiki. These screwdrivers also worked well with Philips. I had to purchase ISO screwdrivers through Eiki; a company in Kobe, Japan manufactured the tools. After the big earthquake in Kobe, the manufacturing company did not rebuild. The present-day Eiki has no historical knowledge of the ISO screwdrivers or that they had even used these screws. The "ISO screw" that I remember -- and still see in VCRs (soon-to-be-extinct also) and other Japanese manufactured goods has what I would describe as a "dimple" or a depression/dot between two sides of the "X." I lost my notes on how to regrind a Philips blade to fit these screws. Any suggestions? This was a great article! When I saw it I immediately read it to see if you had encountered the "Eiki ISO" and I also learned about things I haven't seen. Thank you!
re # 10 As I understand, the fundamental quality of Phillips screwdriver bits is the taper on the driving faces which allows the bit to "cam out" of the recess at an appropriate torque setting with automated machine driving. As driving with a hand held bit (either simple screwdriver or electric) cannot guarantee a precise downward force, the chances of stripping the recess (or damaging the bit) are increased markedly. The ISO, JIS and Pozidrive bits, on the other hand, have parallel faces on the driving flanges, thus will not "cam out ) but will break the recess or the bit, or strip the thread, if excessive torque is applied. Thus it would be reasonably easy to re-profile a parallel sided bit (ISO, JIS or Pozidrive ) to make it fit Phillips screws but exceeding difficult to parallelise a Phillips bit ( I know because I just tried on an old Phillips bit, you would need to be very desperate) It would be far easier to file up a piece of annealed tool steel rod to the right profile and temper it (or anneal the old driver, re-profile and re-temper)