Thanks for the detailed investigation.
I'm not really any further than before. Some of my screws do not fit a
new phillips driver well, others fit perfectly.
Not all of those which don't fit well have the dot. They also don't
fit any other driver (pozi, other phillips sizes).
A phillips 1 with the tip shortened does fit better than a phillips 2
on some of them.
The description of a smaller web (smaller radius) seems plausible
looking at how the misfitting screws interfere with the driver.
I have one cheap bit that is ground with virtually no radius and it
goes in further, but is not perfect, either because the angles are not
right or simply because it is a cheap bad bit.
There definitely is a standard for camera screws, JCIS 8-70, which is
different from phillips and seems to be used mostly for smaller
screws. I was unable so far to find the standard itself or reliable
drawings.
<>
In case you are wondering, no I'm not obsessed, not much anyway.
ST
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On Sat, Oct 27, 2012 at 9:24 PM, Tom Jobe <tomjobe@...> wrote:
I heard back from another retired Honda person on this question about the
JIS vs. ISO vs. Phillips question.
Apparently the Honda screws with the single dot on them are the ones that
have the newer ISO thread combination, and the older screws with the JIS
thread combination have no dot on them. This is reported here:
As far as any of us know the shape of the "+" recess in the head of the
screws did not change when they made the change to ISO threads beginning in
1967.
The friend who is the most knowledgeable of the three of us, thinks that all
of the Honda screws have the JIS variation of the Phillips shape in the
screw heads.
This friend worked on a problem situation years ago where removing some
Honda screws was very difficult out in the field, and the best solution they
found was this Snap-on driver bit. These Phillips "ACR" driver bits
completely solved the problem they were having.
The picture on this web page shows you the "teeth" they put on these Snap-on
"ACR" driver bits, and this link is for the #1 size driver bit.
Thinking back on things that happened using the Honda screws, I remember
having to grind the sharp point off of Phillips screw drivers to get them to
fit better in the Honda screws, which helps support the idea that the screws
are in fact JIS, and not a true Phillips shaped recess.
I have a new set of Kowa brand "T" handle screw drivers and sockets. They
are the ones often used in Japanese motorcycle maintenance, and I assume
that they are whatever is used in Japan (JIS or Phillips?). When you compare
the Kowa screwdriver tips with nice Snap-on screwdriver tips there is not
much difference. I will take a closer look and get some measurements and
pictures of them.
tom jobe...
PS A little later, a close look at the Kowa screwdrivers and some nice old
Snap-on Phillips screwdrivers shows no functional difference. The Kowa tools
being new seem to "grab" the Honda screws a little better, but only because
the old Snap-on tools are worn a bit smoother from use.
I'm still amazed at how well the new Pozidriv screwdriver works in the old
Tektronix Posidriv screws!
----- Original Message -----
From: "Tom Jobe" <tomjobe@...>
To: "TekScopes" <TekScopes@...>
Sent: Friday, October 26, 2012 4:01 PM
Subject: Fw: Question about JIS fasteners
Below is the first reply I got from a knowledgeable Honda friend.
The link he included explains the thread pitch issues between the older
JIS and the newer ISO thread standards.
He doesn't believe there is a difference where the screw driver goes into
the screw, between JIS and ISO.
tom jobe...
As far as the Honda thing goes, this is what i believe
I haven't really looked at phillips head screws lately.
For sure, during the late 60's and thru the 70's, this was the rule-
JIS and ISO used different thread standards.
The JIS screw heads were unmarked.
The ISO heads had a punch mark.
I never read about the "+" being different from one another. (where the
tool fits)
The JIS were supposed to have stopped being spec'ed on Honda machines
around the late 60's or, early 70's, so i didn't hardly worry about this
situation because the earliest bike i worked on (for real, not just a
flat
tire deal) was a 1969 and i'm pretty sure it was ISO by then.
I thought i would check this with the world
Take a look at this site
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