I've recently had some problems trying to adjust the azimuth of a walkman. The screw shows serious wear and I could not turn it, no matter which screwdriver I use, so I started to ask myself if I have the proper screwdriver.

We all know that there are slot and cross screwdriver, but do you know which types are there and which one fits best on every screw? No, right?

Ok, so after searching information in the Internet but specially in the Wikipedia, which is a truly valuable source of information, I've learnt that there are many types of screwdrivers, but regarding our beloved gadgets we mainly focus on cross ones, and the most important are three:

• Phillips type
• JIS type, and
• Pozidriv type

What are the differences between them? I bet all of you, like me, think they are all the same, but there are slight differences that makes only one will match perfectly. That's is specially important for those very hard to loose small screwdrivers that you often find, and makes you spend a hard time.

The three main screwdrivers.

Phillips is the most known one (at least for its name) and it wasn't designed by the inventor of the cassette but by John P. Thompson who after some time sold it to the Phillips screw company. It was designed to cam out when the pressure is high, avoiding damaging the screw when it's fully screwed. The heads are usually named as PH1, PH2...

JIS stands for Japanese Industry Standards and this kind of screw is actually called JIS B 1012. It's used by all japanese manufacturers, so yes, you'll find them in any SONY, AIWA, Nakamichi and all those japanese gear. Be careful because it looks like a Phillips screw, but it was designed to not cam out. A JIS screw is clearly identifiable by a single dot in one side of the cross.

Pozidriv is an improved version of the Phillips with better engagement and less prone to cam out. You barely see it in gadgets, but in wood forniture. This kind of screw is clearly distinguished by tik marks at 45º from the main grooves. These heads are usually named as PZ1, PZ2...

The three main screws. You may look for the single dot in the JIS and the 45º cross in the Pozidriv.

And here's the schematics:

Phillips and JIS schematics.

The main problem here in Europe and US is that there are very few sources to buy authentic and precise JIS screwdrivers, and they are often expensive. You can find them in eBay and other online stores. Here in Spain is rare to find them in hardware stores. One good brand is Vessel, which makes a very wide selection of tools. I recently ordered this set for my walkmans:

Vessel precision set TD-56S.

Also Hozan makes good tools.

Be careful when searching for information about these standards, because there are a lot of misinformation out there. For example, this schematics:

This schema is wrong. In the photo the JIS shows 'rails' into the main grooves, but there are no rails into a JIS head.
The Phillips graph also shows a big round interior but it's not rounded.

Or this one:

This schematics also show rails into the grooves again.
Surprisingly, the graph under it shows it right.

After learning this, I went to check my set of screwdrivers and found that it needs replacement. Here's my set:

My set of screwdrivers, which contains a mix of everything.

In a close view I realized that the orange and the blue are Phillips and JIS respectively. The quality is standard, but I'd like to get chrome-vanadium heads soon, which are much harder:

The blue one is JIS, although with a bit pointy head, and the orange is Phillips.
Actually I was using the orange when opening my decks. Sigh!

But the other two were weird; the green one is a modified version of the Phillips (notice that the grooves aren't symmetrical) and the small one (which I was using for walkmans) is actually a Pozidriv (!):

The green one is a weird version of the Phillips and the small one, a pozidriv.

So, basically the question is: can I use my Phillips screwdriver with a JIS screw? Well, yes you can, but there's a high probability that you end damaging the screw and even the screwdriver. The Phillips system is aimed to cam out when excessive presure is applied, as an 'self-saving' system. The JIS system aims the person to regulate the pressure, not the screwdriver, allowing for a more precise adjustment. Using a Phillips with a JIS screw can easily wear the screw and even damage it.

This is what happens when you use a Phillips screwdriver into a JIS screw.
Curiosly, the opposite is not that bad.

This photo shows more clearly what happens when you use a Phillips screwdriver into a JIS screw.

So, yes, if you do care about your gadgets you should invest in a good set of JIS screwdrivers and stop damaging your screws. Every screw need a proper screwdriver.

The real deal: a high quality screwdriver with a JIS screw.

PS: And when you end up with a screw with the head wear and it's almost impossible to unscrew, did you know that there exist screw remover tools? Yes, you have to dig a small hole in the center of the head and put this tool into and start turning it in the opposite direction. When it finally engages the screw, it pulls it out.

A screw remover tool.