Shop Press

Shop Press is the news and idea hub for everything related to working on cars and trucks, focusing on repair, technology, and wrenching lifestyle.

From the creative minds at:


Hot Off the Press

Texas nonprofit helps low-income vehicle owners afford auto repairs

At any given time, about 1 in 5 vehicle owners are delaying some sort of auto repair, with the most common reason being that they can’t afford it, according to the Auto Care Association Factbook. All this deferred work adds up to an estimated $31 billion that drivers...

A day in the life of a service writer (VIDEO)

The hardest job in an automotive shop might just be that of the service writer. Taking heat from the boss, the techs, and the customers isn't easy. That the role is for dynamic individuals becomes apparent quickly when considering the tasks that make up the job. Watch...

Serviceability Hall of Shame: Ford Taurus Spring Shields

The Serviceability Hall Of Shame was born from all the times we’ve looked at a vehicle and realized some usually simple task was going to be nightmarish. It is, ultimately, a response and explanation of the inevitable question, “Good Lord, why?!” Today’s entrant isn’t...

January Automotive Horoscopes

Aries: You may not think of some of your repairs as innovative, but a creative fix is a creative fix. Your outlook is out there, and that's OK. Expect to see someone else cribbing your notes but remember to take it as flattery. Not everyone has the same gift of seeing...

It’s totally fine to run your fuel tank down to empty

One of the pieces of automotive wisdom that’s been repeated by publications and mechanics alike for ages is that it’s not good to run a fuel tank below some arbitrary fill point, like a quarter of a tank. At some point, that probably wasn’t bad advice. But today? It’s...

LOF PSA: Don’t forget the lube job

Please forgive me, because I’m about to be a dinosaur and proselytize for a few moments. Many moons ago, I would have customers request an oil change and a lube job. It was so prevalent that the acronym for this, LOF, is still in pretty common use. (That’s “lube, oil,...

Best of Shop Press 2022

Shop Press officially launched in March 2022, at least if you go by the press release. Between then and now, we’ve published well over 100 articles and videos dedicated to auto repair professionals and wrenching enthusiasts. We greatly appreciate everyone who has...

The other “Phillips” head screwdriver you might not know about

by | Dec 9, 2021

Not every Phillips head fastener is a Phillips head fastener.

I believed this was common knowledge until today, when I was speaking with another tech who had no idea what I was talking about, and I relived a lesson from my salad days of wrenching.

Many moons ago, when rebuilding the carburetors on Japanese motorcycles, I would replace all the hardware for the bowls and carb tops on CV units, for they were constantly stripping. I used to poke fun at them. I said they were made of cheese.

An old mechanic saw me doing this on a nice older bike, and told me I was an idiot. Quite naturally, I asked him why. He told me I was using the wrong tool on them. Nonsense! It’s a simple Phillips-head! Why, I had drawers full of them. He laughed and told me to bring him one of the screws I was throwing away. With his tobacco-stained pinky nail, he pointed to a small dot in one of the corners of the cross.

Dimples in a screw denote they are JIS.

See the dimples? Those are JIS shorthand for, “Walk back to your box and get the correct tool!” Photo by Lemmy.

“See that?” he asked. “That punch mark is to tell you not to use a Phillips-head driver on it. This is called a JIS screw. Japanese Industrial Standard.”

I thought he was breaking my horns. Then I looked into it. Turns out, he was correct. A true Phillips head screw “cams out” at a fairly low torque reading—exactly why I thought they were stripping (and why you’ve probably stripped them too). No one is sure if the design was developed that way, but the patent was updated in 1949, when that very cam-out “feature” (useful for machine-driven fasteners in those days) was described.

JIS screws are a little different but look similar. Many, many items made in Japan use JIS screws, which have a different profile in the “cross” area, as well as a more vertical angle of attack in the head of the fastener. They’re also flat in the bottom, whereas a Phillips bit is not, so it stands out of the slot when inserted, decreasing the contact area between driver and fastener.

JIS screwdrivers prevent damaged JIS fasteners, and they also can be useful for a Phillips fastener that’s been marred—sometimes prudent use of a JIS driver can extract the Phillips fastener. (And if you get it out, replace it with something fresh so you don’t sweat the same thing twice!)

Phillips screwdriver next to a JIS screwdriver

Not all screwdrivers (nor fasteners, for that matter) are created equal. The one on the right is a JIS driver. Photo by Lemmy.

I’ve got a few brands of these kicking around in my box, but I think Vessel makes some really nice ones. They’re expensive and always have been, and they are worth every penny. I recommend them.

Related Articles

Notify of
Oldest Most Voted
Inline feedback
View all comments
Click to leave a comment!x

Get Articles In Your Inbox

Subscribe to receive a monthly email summary of our latest Shop Press stories.

Shop Press

Thanks! You're now subscribed.