JIS screws/drivers

[rmcphearson]

Ok, ok, I've been turning wrenches and screwdrivers for a number of years and it's about damn time I figured out what the hell the deal is with JIS screws/drivers. I tinker with a fair amount of Japanese made engines and carbs so I should be able to put what I have learned into practice soon (I'm working on a Daihatsu with a carb issue today). Here is what I have gathered so far:

1) "The JIS B 1012 is commonly found in Japanese equipment. It looks 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." -Wikipedia

2) JIS bits are not available from McMaster-Carr or Lawson (my preferred vendors) but the entire screwdrivers are available from McMaster. I'm ordering the set of (3) 53325A61 for $38.37. Oddly, I can get a bit set with dozens of different typical and exotic shapes (pozidriv, torq-set, tamper-resistant hex, torx, Dooly's mountain dew driver, Tanya's twirl twister etc.) but no JIS bits.

3) JIS screws are available from McMaster but only in metric sizes. My Daihatsu is missing a screw on the carb and my dealer can't get it. I might order a small screw assortment.

4) Are JIS screws better since they are "designed not to cam out"?

5) Were phillips designed to cam out?

-Roland

[Joe Rogers]

#4 Yes if you have a properly fitting screwdriver.
#5 Yes the phillips design is designed to cam out instead of stripping the screw or wringing off the screw head. Both features more suited to the products available when the patent was issued.
Joe

[Doozer]

I really really really wanna see Tanya's twirl twister.

-D

[Benta]

The Wikipedia page on JIS fasteners is total cr*p, please ignore it. It references miniature fasteners for electronics, a completely different thing.

Owning a Japanese car, I've been through this whole thing myself, even buying original Japanese JIS screwdrivers.

I'm wiser now, but lost a bit of money.

Inspecting the JIS screwdrivers under a microscope reveal that the profile and angles are the same as Philips with one caveat: the point is shorter.

So take a PH2 (or whichever size you need), grind 0.8...1 mm off the point and you have a screwdriver that will slot into JIS fasteners perfectly.

BTW, JIS screws are always metric. Up to 6 mm, you can normally use standard metric coarse screws. For 8 mm and larger they tend to be metric fine in automotive applications. Size mentioned is not head size, but thread size.

[gambler]

The Wikipedia page on JIS fasteners is total cr*p, please ignore it. It references miniature fasteners for electronics, a completely different thing.

Owning a Japanese car, I've been through this whole thing myself, even buying original Japanese JIS screwdrivers.

I'm wiser now, but lost a bit of money.

Inspecting the JIS screwdrivers under a microscope reveal that the profile and angles are the same as Philips with one caveat: the point is shorter.

So take a PH2 (or whichever size you need), grind 0.8...1 mm off the point and you have a screwdriver that will slot into JIS fasteners perfectly.

BTW, JIS screws are always metric. Up to 6 mm, you can normally use standard metric coarse screws. For 8 mm and larger they tend to be metric fine in automotive applications. Size mentioned is not head size, but thread size.

this is correct, we even grind the tips of our impact driver bits to work on jis screws.

[Willy]

Yup I too have done that and it does work although on a really stubborn screw I have had better luck using the JIS bits.
Not always required for sure but when push comes to shove it does give one the edge due to better contact and engagement.

[Benta]

Willy. I've seen those pictures before, they come from someone selling JIS screwdrivers. Forgot who.
They are somewhat misleading. A PH is not as pointed, and a JIS is not as blunt as pictured. It's a worn-out PH and an almost-new JIS.
Here is a link to better pictures: https://www.dateelectronicsupplies.c...jis-standard/4

As you can see, angles and cross section are very close. My experience is, that a shortened PH settles perfectly. And under a microscope, there was practically no difference, except for the point.

[gambler]

The screws that hold the rotors on jap cars are brutal tight sometimes, this tool works about 50% of time. Attrition rate on bits is high.

[Benta]

Buy Wera or PB Swiss. Walmart ain't the solution.

[gambler]

those broken bits are straight off the MAC tools truck.

[Willy]

Willy. I've seen those pictures before, they come from someone selling JIS screwdrivers. Forgot who.
They are somewhat misleading. A PH is not as pointed, and a JIS is not as blunt as pictured.
Here is a link to better pictures: https://www.dateelectronicsupplies.c...jis-standard/4

As you can see, angles and cross section are very close. My experience is, that a shortened PH settles perfectly. And under a microscope, there was practically no difference, except for the point.

No argument from me as I've done the same with good luck. The difference can be subtle especially when you consider that there are literally thousands of suppliers of the Phillips drivers, sometimes it seems that the standards seem to get blended. The video you linked to does illustrate the difference graphically though between the unaltered Phillips vs the JIS drivers.

It is also interesting to note that Phillips has seen the issues associated with their original design and the cam-out problems associated with them. They have now what is called the Phillips II drive system that features what they call ACR, or anti-camout-recess technology that consists of a driver and screw, although it is claimed they are field serviceable with conventional Phillips drivers.

https://phillips-screw.com/drive-system/phillips-2

Just what we need, another cross point system.

[Benta]

those broken bits are straight off the MAC tools truck.

First time in my life I've seen bits broken like that. Dunno what MAC Tools supply, but it looks over-hardened.

[Willy]

The screws that hold the rotors on jap cars are brutal tight sometimes, this tool works about 50% of time. Attrition rate on bits is high.

Yes they can be a real pain in the butt I agree!

Have you tried the Shake'N Break air hammer attachment? They have been as good of an investment for me as anything else I've tried. Used correctly they have helped me a lot.

https://www.vehicleservicepros.com/in-the-bay/tools-equipment/tool-accessories/impact-sockets/product/21000014/mayhew-tools-2pc-shake-n-break-socket-adapter-set

[lynnl]

Well, I'm still confused. That picture shown in Willy's post #6 above shows the phillips as being distinctly longer and pointier, which goes along with the comments about grinding off a bit from the tip of the p.h. to fit the JIS screws.

...But at about the 1:20 point in that video in Benta's link, i.e. https://www.dateelectronicsupplies.c...jis-standard/4
that narrator describes the JIS as longer and pointier, tho the words he uses are "...the teeth are longer and pointier..."

[lynnl]

Buy Wera or PB Swiss. Walmart ain't the solution.

Benta, do you know if "Wera" tools and "Wiha" tools are related, or the same company? (both are German) I have a set of Wiha small/precision screwdrivers; they're really nice.

I first became familiar with the Wiha name when I found a Wiha anti-static tweezer in the parking lot at my (electronics mfgr) employer. I was amazed at the precision and quality of it.