JIS screwdriver A MUST-HAVE TOOL (Japanese industrial standard) Phillips, and JIS screwdrivers explained and differentiated

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F 18 Driver

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Oct 1, 2023
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Hi everyone,


Further, I would recommend a JIS screwdriver with a built-in impact (built-in impact driver)… Which I have listed below with a picture vessel 980

Below are not my words but I'm going to quote articles for this treatise from the Internet and include a few pictures in order to save time.

"It is rather hard to believe, that after all these years of mangling Phillips screws on Japanese bikes, more people (many of them professional mechanics) don’t know about JIS screwdrivers – Japanese Industry Standard.

so you re telling me that s not a phillips

Looking at a JIS tool next to a regular Phillips screwdriver, most people are hard-pressed to tell the differences, but they are definitely there.

Ninety-percent of the time, a regular Phillips will work on a JIS screw; but it’s that other 10% that gets us swearing, then throwing things – those tight screws holding on your carburetor float bowls being particularly devilish once they’re past about two decades of non-removal.

That’s when the right tool can make all the difference. The right tool is a JIS screwdriver, which just fits better in a JIS screwhead and is designed to let you apply more torque than a Phillips driver.

"The Phillips system was invented for use in assembling aluminum aircraft, with the object of preventing assemblers from tightening screws so tightly that the aluminum threads strip.

The driver will “cam out” before that happens. The Phillips driver has four simple slots cut out of it, each slot is the result of two machining processes at right angles.

The result of this process is that the arms of the cross are tapered and has slightly rounded corners in the tool recess.

Phillips is designed so that when excess torque is applied it will cam out rather than ream the recess and destroy the bit.

Japanese Industry Standard: Often improperly referred to as Japanese Phillips. Commonly found in Japanese equipment, JIS looks much like a Phillips screw, 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.

Most people and companies outside of Japan have absolutely no idea what they are. With the similarity in appearance to the Phillips the screws are often damaged in removing and installing with the wrong tools.

JIS tends not to cam out like Phillips. The JIS driver can be used on Phillips quite easily but not reciprically
(sic). Drivers are easily available in North America, try Amazon and/or eBay.

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)."


Easily available via Amazon or eBay

This Vessel Megadora 980 Impacta P2x100 #2 Cross Point Impact JIS Screwdriver, which combines an impact driver with a screwdriver, will save you untold grief . An internal cam mechanism turns the tip 12 degrees per hammer blow


Non-impacted JIS screwdrivers
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Well-Known Member
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Sep 18, 2023
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Central Missouri
I would be careful with a hammer-type impact driver because it puts a lot of stress on the aluminum part the screw is mounted in, that is especially the case if it is just an aluminum mounting ear which breaks off easily.

Besides the above it is probably a good addition to any toolbox. Luckily, all the major engine casing bolts on a Vmax are already Allen head screws. Now, Japanese vintage bikes (like my Kawasaki H2) had all Phillips or, I guess JIS screws.

Tom Determan

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Oct 11, 2019
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Great write up guys.

My buddy informed me about this about 15 years ago so I have that Vessel set in all my toolboxes.

Why didn't someone, ANYONE, tell me this about 60 years ago ??!!!!! I mangled countless case screws on Suzukis and Yamahas back in the 70's, especially the ones in the lower front corner by the primary or the flywheel that was full of dirt from the front tires. (Before we all bought $300 pressure washers to keep our MX bikes looking new)

I still have 6 mm screws hanging around my bolt bins with chisel marks, LOL.
Jul 23, 2023
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Solomons, md, usa
That's a tough question. Needless to say, the Vmax is much quicker in a straight line. I guess the KZ1100 is like a late 70s-early 80s "superbike" on steroids. The Vmax is like a mid 1980s muscle cruiser on steroids. Both great rides in different ways.

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