Why do people do this ?

[manny]

Just a little nit-picking.
Seems like everytime somebody refers to a bolt, they call it 10 mm, 14 mm, 17 mm,... whatever.
What they actually MEAN is the size of the bolthead.
I believe the only people dealing in these " Industrial - strength " bolts, are heavy equipment mechanics.

[chazola]

they do it just to annoy you

When someone calls a bolt that takes a 10MM wrench a 10MM bolt they are just showing their ignorance.

The only people that realize that this is not a 10MM bolt is someone who sells hardware or someone who has done enough work that they have to go buy bolts, taps or dies.

Have a great day,

[MTI]

Okay, I'll ask . . . what would be the proper nomenclature to describe the hardware at hand . . . a metal threaded fastener that would require a 10mm wrench or socket to affix or loosen?

[whunter]

Here are three that I replaced today.
10mm x 8 x 1.25
13mm X 8 x 1.25
14mm x 8 x 1.25

the trick is to get the right bolt in the correct hole.
The other trick is to make it look easy and when you are done, they can not tell that you ever touched the car.
A true master mechanic does both.

[fj bertrand]

aren't they called cap screws? a 10mm is 6mm screw diameter
or is that whitworth? or is it British standard? So it goes.....

[whunter]

Head, Shank, thread pitch.

The term capscrew does not refer to the bolt itself, rather how it's used. If used as a bolt, there is a nut used. If the "bolt" screws into something like a head or block instead of getting a nut on it, then it is being used as a "capscrew." So the same "bolt" may be used as a bolt or a capscrew.

Have a great day,

[Q]

I believe the point that is missed here is that this is a sort of DIY forum category for the most part. If I'm going to go tackle a job on my car, it's nice to know what tools I'm going to have to crawl under there with. Knowing the pitch, length and shank dimension is absolutely useless to me until I need to replace one.

[sbourg]

I'm with 'Q' - the only times I need more info than the headshape are if I need to replace a bad bolt, or if the correct torque for the part isn't listed and I have to consult torque tables.

Steve

[csnow]

Ok, it's not technically accurate, but doesn't everyone know what is meant? And is that not what is most important? It's not like you are going to find a lot of 14mm bolts on a car.

[Jackd]

When will the USA finally switch to the metric system and be in line with all other modern countries?????.
The old archaic english system is certainly a cause of a lot of stripped bolt heads in the US.
Anybody tried to use a 1/2in. socket on a 10mm bolt head??

[JoeR]

Why are metric sockets either 1/2" or 3/8" drive?? ;-)

[moruzzi]

In a DIY forum the head size is usually important. If your replacing the screw or bolt the rest of the info is at least as important.

Just to be technically accurate whether you call something a bolt or a screw is dependant on how it is used.
"If a product is designed so that its primary ourpose is assembly into a tapped hole, it is a screw. Thus the screw is tightened by exerting torque on the head. If a product is designed so that it is intended to be used with a nut, it is a bolt. A bolt is tightened by exerting torque on the nut" Mechanical Engineering Design by Joseph E. Shigley

That said even in the Mechanical Engineering world fasteners are usually refered to as screws when they are small and have a slotted or philips head. Bolts are larger sized fasteners with hex heads even when they are used as a screw in the definition above.

Paul
1984 300SD
1992 400E

[brewtoo]

Well, if a bolt accepts a 10mm socket, I'm still gonna call it a 10mm bolt and proudly display my ignorance.