JIS screws

Coleroad

Coleroad

New member
Are jis screws common knowledge? I thought it was. What leads me to asking is prompted by a call from my nephew yesterday. He was having trouble with a rotor screw. I asked him if he was using a Phillips head or a jis screwdriver. To my surprise he had no idea there was such a thing as jis. I wasn`t surprised he didn`t have a jis screwdriver of his own, but I thought he knew about them. Japanese cars for years haven`t had Phillips head screws in them. They`ve all been jis. Even U.S. auto manufacturers use them exclusively anymore. Using a Phillips head screwdriver in a jis head screw makes for a great chance of stripping the screw out.
 
Is that what used to be known as a Posi-Driv screw?

And no, are you kidding? You`re lucky if the average person knows the difference between a slotted and a "cross-recess" screw.

I mean even I didn`t know there was a separate JIS standard, I just looked it up (so ignore my question about Posi-Driv)...and I guess that explains how I cammed out and had to drill out that screw holding my door latch in when the lock solenoid went bad.
 
JIS stands for "Japanese Industrial Standard", which , as the name implies, is Japan`s manufacturing industry metric standard that is "different" than the ISO (International Standards Organization) for metric fasteners.

You are correct in saying that the JIS cross on screw is "different" than a Phillip`s cross on a screw, and yes, you can strip them out IF you use the wrong type of screw-driver. It is much akin to trying to remove a metric hex-head screw with a SAE (AKA fractional inch) hex socket that will, indeed "fit" a metric head, but be slightly loose and, hence, you could round off the corners of the hex head.

Europe and Russia uses ISO metric standards, the United States has SAE (Society of Automotive Engineers) for the Imperial (English Inch) system, and Asia JIS for its metric applications. The "problem" is when a manufacturer tries to engineer a machine with components from all three different world manufacturers and their standards, it creates a REAL headache for designers and service technicians. It is one of the reasons that "some" European Union nations will accept ISO metric standards for imported machinery ONLY.

One thing I do like about Japanese fasteners is the use of Hex-head screws with a JIS cross on them on some larger sizes. I would rather use a metric hex socket than a JIS screw-driver to remove a screw, but it does allow the flexibility to use either.

I think though that your point is "How do I recognize a JIS cross on screw from a Phillips cross?" One way is that the cross slots are somewhat "narrower" or "thinner" than a Phillips. Then again, how do you recognize a metric hex head from a SAE inch hex head? Well, you need BOTH types of sockets to tell because you are using the hex of each type of socket as a gauge to tell which one fits better. Sometimes markings or letter initials on the hex itself will tell if it is metric or SAE. You would need to be trained mechanic or engineer who had familiarized themselves with such markings. But with a cross-slot screw, you don`t have such markings, so you again need BOTH types of screw drivers (JIS tipped and Phillips tipped) to use as a gauge and see which one fits better. That, to me, is the "shade tree mechanic`s" way of determining which is which on the screw(s) you are trying to remove or tighten.
 
Lonnie said:
You are correct in saying that the JIS cross on screw is "different" than a Phillip`s cross on a screw, and yes, you can strip them out IF you use the wrong type of screw-driver. It is much akin to trying to remove a metric hex-head screw with a SAE (AKA fractional inch) hex socket that will, indeed "fit" a metric head, but be slightly loose and, hence, you could round off the corners of the hex head.
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Thats a a great analogy.
 
I didn’t realize “JIS” was a thing. I did know that different Phillip type screws have different type/size slots. I’ve got at least 4 different screwdriver head sets and I always try to find the one that fits without slipping out. There are too many “standards” out there.

In a similar vein, did you know that German license plate holding screws are a different size than Japanese screws? I bought a used BMW from a Hyundai dealer and they had to go to the BMW dealer to get the correct size screws. A normal 2 minute job took over an hour. We (yes we) took off license plate screws from several makes and models before the call was made to go to the BMW dealer.
 
Accumulator, you and I couldn`t be more alike in this respect and our preference for older cars. That`s me embracing geezerhood.
 
When did US automakers start to use them (exclusively)? Curious as the `08 Crown Vic, which has a weird mix of metric/standard fasteners, doesn`t have them.
 
Accumulator said:
When did US automakers start to use them (exclusively)? Curious as the `08 Crown Vic, which has a weird mix of metric/standard fasteners, doesn`t have them.
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Thats a typo on my part. It should be U.S. automakers use them too. Japanese makers use them exclusively. Any rotor screw I`ve come across the jis screwdriver fit much better.


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rlmccarty2000 said:
I didn’t realize “JIS” was a thing. I did know that different Phillip type screws have different type/size slots. I’ve got at least 4 different screwdriver head sets and I always try to find the one that fits without slipping out. There are too many “standards” out there.

In a similar vein, did you know that German license plate holding screws are a different size than Japanese screws? I bought a used BMW from a Hyundai dealer and they had to go to the BMW dealer to get the correct size screws. A normal 2 minute job took over an hour. We (yes we) took off license plate screws from several makes and models before the call was made to go to the BMW dealer.
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Yeah, I knew about the BMW license plate screws... :)
Dan F
 
I`ve read the JIS is harder to srip out. I`ve also read that Phillips work fine if you grind the tip flatter. You can find inexpensive JIS screwdrivers on Amazon.
 
Setec Astronomy said:
Lonnie, did you live in Detroit back in 2008? Or do I have you confused with another member?
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NOPE, have never lived in the Detroit area ever. Did visit the area, though, after Autopian All-Star Dave Fermani posted his photo expose on abandoned detailing shops/businesses in the Detroit area. Please see linked thread: (No pun intended, since this thread IS about screws)
https://www.autopia.org/forums/car-...hop-pics-33-33-33-33-a.html?highlight=Detroit
You would not be "confusing" me with him, would you??

Related topic though: I do like Torx socket head screws, but the cost is almost 4:1 over "conventional" (Phillips recess) screws due to the patented socket-drive shape. Ah yes, ANOTHER socket shape that requires MORE specialized tools. Don`t even talk about the ones with the "post" in the middle to make them "tamper-resistant" (MORE specialized tools!). Still a VERY good fastener drive system that does not strip out easily and was really developed for mass production assembly efficiency and assembly installation tool longevity.
Then again, I`ve run across Square socket screws on residential doors and RV metal paneling (Still MORE specialized tools!).
Oh yes, lest I forget, the screw for a 2-liter Ford Capri engine`s cam belt tightener is a 12-stared socket that requires a special Ottumwa Tool Company tool to remove (according to the Ford Service Manual). I do not remember what I paid for it back in 1981.

Yes, I have tools (too many, according to my significant other) that look brand-new due to their "infrequent" use. I have always subscribed to the theory, "the right tool for the right job." However, my mechanical prowess is akin to what Phyllis Diller said about her husband Fang: "When you put a hammer in his hand, you have roughly two objects with the same IQ!"
 
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