Japanese Phillips Screws

[joeswamp]

OK, maybe most of you know this already but I just learned about it recently and so there have to be at least a few folks here that are unaware...

I've always heard that Japanese screwdrivers fit Japanese screws better, but I always thought it was maybe some industrial tradition in Japan to make them all at one end of the spec or something. Turns out Japanese Phillips screws are quite different from US ones, they're made to a totally different spec (the "Japanese Industrial Standard" or JIS, where the US spec is ANSI) and the heads are even stamped with a small identifier. Next time you're at your bike, look at the screw heads. If there's a dot next to the slot, then the screw is JIS Phillips, not US Phillips. My Triumph has these things all over the place because a lot of the subassemblies are Japanese.

Here's what the dot looks like:



Even though the screw in this picture is stripped you can still see the dot above the remains of the slot. If you come across one of these screws and it's tight, be very careful and exert a lot of pressure while removing it, as there's a good chance it will strip with a US screwdriver. Smaller screws seem to fit worse, e.g. lots of folks strip the little screws that hold float bowls on carburetors. If you google "JIS screwdrivers" you'll find a lot of angry folks on various forums that have stripped screws on model airplane engines and on old cameras.

If the situation appears risky you might want to order up a set of the correct screwdrivers. You can get a cheap set from:

Precision Screwdriver Set: Japanese Industrial Standard

or if you're a tool junkie you can get high quality from

- VESSEL Tools

The weird thing about this standard is that the big tool companies (Snap-on, etc) don't seem to make JIS screwdrivers -- which is odd in that you'd figure they'd be on all Japanese cars. The only folks that seem to make JIS screwdrivers are, well, Japanese screwdriver companies...

[Wishbone]

NEVER heard of that

Good heads up!

[ZX-12R]

I thought they stripped because they use cheap white metal fasteners that are very soft relative to a hardened steel screwdriver.

[elwood206]

Good to know, thanks.

[Tricky Mike]

Dirty:

[JohnnyV]

I know exactly what you're talking about... after replacing an engine case cover on my '65 CB160 that had NEVER been cracked open, it was a bitch and a half and about 50% of the screws stripped. Luckily I had the spare motor that the good case cover came off of so I had plenty of good screws left.

[markbvt]

JIS screws are a pain in the ass, and I do not understand why JIS screwdrivers are so hard to find in the US. Even worse, JIS bits (for use in a typical screwdriver bit holder, electric screwdriver, etc) are freaking impossible to find.

I've heard that if you take a standard Phillips screwdriver or bit and grind a small amount off the tip (just grind it flat), it will work much better in a JIS screw.

The sensible thing to do is to replace any JIS screws that you commonly need to access (eg, carb bowl screws, etc) with stainless steel hex-head ones.

--mark

[joeswamp]

I agree these little bits are hard to find, so strange that few companies make them. You can order them from Vessel as part of a couple of kits:

Stubby Ratchet Screwdriver

Flat Plate Ratcheting Screwdriver Set

Fortunately not all of the screws on our bikes are JIS, the key is looking for that little dot on the screw head. Lots of stuff that's owner servicable is typically US Phillips. The screws that hold the brake reservoir cap on my SV are US Phillips, as are all the screws that hold on the tail and turn lenses on my Triumph. It's only when you start impersonating a mechanic that you begin to need these screwdrivers.

[joeswamp]

I thought they stripped because they use cheap white metal fasteners that are very soft relative to a hardened steel screwdriver.

I used to think that as well, but in actuality if you use the correct driver those little screws can handle a lot more torque than a US Phillips. The JIS design is superior.

The original US Phillips is one of those designs that should never have become a standard, kinda like the QWERTY keyboard or Microsoft Windows. You actually don't see too many US Phillips screws used in high volume manufacturing anymore, most companies these days have switched over to Torx.

[markbvt]

Flat Plate Ratcheting Screwdriver Set

That actually looks really useful, but how do you know the bits are JIS? I didn't see any mention of it anywhere.

--mark

[joeswamp]

That actually looks really useful, but how do you know the bits are JIS? I didn't see any mention of it anywhere.

--mark

I'm just guessing they are because I don't think Vessel makes US spec bits. From their insert bit catalog page:

http://www.vesseltools.com/bits1.pdf

"VESSEL is known for their high quality and ensures that every product supplied is manufactured and tested to the relevant quality and production standards as JIS (Japanese Industrial Standard) and DIN requirements."

There's no mention of ANSI standards, so I figure these have gotta be JIS. Also at their main catalog site in Japan there's no distinction between JIS and ANSI, they only sell one kind of bit.

In any case I just ordered that tool the other day so I'll let you know for sure after I get it...

[Jaynnus]

Dirty:

I was thinking the same thing.

[Tricky Mike]

I was thinking the same thing.

Oh really?

[richw]

Impact driver.... only way

When I nod my head hit it

Yes flatening the end works

[Crash Dummy Denno]

Dirty:

[joeswamp]

That actually looks really useful, but how do you know the bits are JIS? I didn't see any mention of it anywhere.

--mark

Tool showed up tonight. The insert bits are definitely JIS, you press them into the fastener and they're wedged in place tightly by friction (unlike the other bits I had). The difference in shape is really subtle, it's hard to tell by eye that they're different from a normal Phillips bit.

I tried them out on a couple of fasteners on the bike and they felt like allen head screws, no tendency to cam out at all -- guess that's reason they came up with this different design. Feels like you could tighten a fastener until the head snapped off.

[Wishbone]

So does it seem like you could grid a bit of the tip of an American screw driver to imitate it?

[joeswamp]

So does it seem like you could grid a bit of the tip of an American screw driver to imitate it?

Some folks say that helps. Honestly, the difference between the shapes is so subtle that it's not easy to detect by eye. Maybe one bit is a tenth of a millimeter longer and the slot is a eighth of a millimeter narrower and the internal radii of the flutes is a quarter of a millimeter different -- stuff like that.

All I can say is that the right tool doesn't strip the screw.

[Degsy]

Son of a bitch, I didn't believe this until I looked at the IBM machines at work (made by hitachi-koki) and on all of those little screws that we keep rounding off are these tiny DOTS o the head.

I have been working on these machines for 22 years and I have never noticed or been told about this. Thanks!! I'll order the tools.

derek

[gmdboston]

Next weeks lesson: Reed & Prince.

[markbvt]

Joe, thanks for the report. I'll order that tool set myself.

--mark

[daviid]

Son of a bitch, I didn't believe this until I looked at the IBM machines at work (made by hitachi-koki) and on all of those little screws that we keep rounding off are these tiny DOTS o the head.

I have been working on these machines for 22 years and I have never noticed or been told about this. Thanks!! I'll order the tools.

derek

[Degsy]

Well, I'll qualify my statement by saying that we keep rounding them off because we have a few techs who think that a phillips screw holding a cover on should be torqued like it's holding in the nuclear reactor core on the voyager space mission.

[978chris]

Well, I'll qualify my statement by saying that we keep rounding them off because we have a few techs who think that a phillips screw holding a cover on should be torqued like it's holding in the nuclear reactor core on the voyager space mission.

i can so relate.

ended up ordering a bunch of preset torque drivers for them... no more stripping.

[akira700]

Thanks for the tip, Joe.

No pun intended!

also Vessel stuff is pretty slick!
They have a glow in the dark driver! Cool shit.