krazik

On the s2k in every example I can think of.

M6's have a 10mm head
M8's have a 12mm head
M10's have a 14mm head
M12's have a 17mm head

RedY2KS2k

MonkeyCMonkeyDo,

DIN is the European standard: M8 bolts have a 13 mm hex head.

JIS is the Asian standard: M8 bolts have a 12 mm head

I'm sure other sizes are different as well, but M8 is so common I know the difference right offhand.

MonkeyCMonkeyDo

i'm sure we have sucessfully alienated and uterly confused any audience this thread may have had.

I should have explained further, I was just trying to tell spitfire he wasn't entirely wrong.

Yes Euro Din/ISO is often different from JIS Japan/Far east is different from ANSI-Metric (B 18.2.xxxxx M) united states. I'm an ME desiging large industrial equipment for a woulrdwide market by trade so I'm definately familiar with the differences, from my rescouces at my desk...

FWIW my resources have JIS B1180 with 13mm across flats for a
Full normal hex bolt, with or without bearing face, but there are probaly less of these non-flanged style on automotive applications.
jis din
m8 - 13 13
m10 - 17 16*
m12- 19 18*

*has changed over the years

I've wrenced at least a handfull of them and i can't say i remember which socket fit anyway but my guess is most bolts save a few on the S are flanged Type JIS B 1189 with (as Krazik put it)

DIN and ISO standard on these flage types exist in a variety of forms. but like the JIS flanged, are smaller across flats the the full hex counterparts. one reason to use them is people often put torque to a bolt by feel instead of an actual torque spec, if I give them a "big socket" they put alot on it. The flange gives a good binding face but a reduced head hex size encourages lower torque application. The bolt can take the torque fine on the way in usually many many times the automotive manual recomended value but when you go to take it out you don't want to twist the head off because it rusted in place. A cleaner environment than a car would see more full hex head bolts torqued alot closer to the yield point, or instead, as is often common, a socket head cap screw.

RedY2KS2k

As for alienating the audience, this is supposed to be the "Technical" sub-forum, isn't it? If I remember correctly, Spitfire S is from the UK and thus probably more familiar with DIN/ISO, so you were correct there. Krazik was addressing Honda fasteners, so both of them were correct.

You obviously know more about these standards than I do. I just remember the old air-cooled VW's "back in the day" required 10, 13, 15, 17, and 19 mm wrenches; 16mm was useful only as a substitute for a 5/8" and 18 mm was useful only as a paperweight.

You're right on point regarding torque: I'd never assemble rod bearings, head bolts, etc. without a torque wrench but I'd also never use one for ordinary assembly of non-critical parts.

Keep the information coming. Should we segue into the differeces between 8.8, 9.8, and 10.8? My knowledge is limited to the "greater than or equal to is OK" school of thought.

SenderGreen

I am enjoying all the technical info in this thread. A little over my head, but most of it seems to make some sense to me. I have nothing to add but thanks.

SpitfireS

RedY2KS2k Posted on Jun 21 2007, 04:38 AM
Close, I'm from the Netherlands, AKA "The Low Countries", AKA "Holland".

(allthough "Holland" is more of an 17th century thing and some Dutch people may be offended if you would think they are from "Holland" while they live in Limburg or other eastern or southern provences )

Anyway...
Yes, I was referring to DIN/ISO (and the Dutch substitue NEN) and bolts used in construction and machinery.

Up until this post I always thought that nuts & bolts in Japanese cars were made with smaller heads to save space & weight.
After looking up the JIS standard on internet I know better: its a complete (DIN based) standard.

What standard would machinery & construction (IOW: non-automotive) use in Japan?

MonkeyCMonkeyDo

much like DIN,BSI,ANSI or other standards JIS applies to many many things, the article number (B1180 in the case of those flange bolts) refers to specifics of design usually dimesional, material properties surface treatments.
Sometimes a standard will specify a specific type of something for a specific application or in the case of ISO9000 an agreed upon minimum procedure ensuring quality manufacuring process. But usually it just references the other standard that describes the dimensional information and doesn't in itself have the dimensions. There are literally thousands of documents for any standards organization, and they are all nested together with tons of cross references.
In the case of a fastener standard like JIS B1180 or DIN 933, there are often sub items referring to thread undercut options aloowances for different methods of manufactrer, or other "options" like if there is or is not a relief to cut the corners on the bearing face making it round for a small portion.
sometime a different root article number is used as in a fully threadded hex cap screw (din933) vs a partially threaded one (din931). basically it's all very organized. Many of the times the most common ones relative to a particular industry are well known within that industry, the documents themselve are not exactly publicly available in their entirety, and companies buy copies from the standards orginization, but often a manufacturer will publish excerpts in their catalog to aid those specifying the parts in what will fit their application.

RedY2KS2k

Sorry, SpitfireS. I should have paid attention to more than the picture of the plane, but those planes are so beautiful I was distracted. ;-)