Phil Ethier wrote:
>
> From: B. Vibert <blur@ican.net>
>
> >Actually, most "bolts" are only screws, until you put a nut on it, then it
> >becomes a bolt.
>
> Haven't heard that one. Where does it come from?
I'm not sure where it originates from, I looked it up quickly and found a
reference in Rothbart's Mechanical Degign Handbook, (highly recommended)
11.2.2 Standards for Mechanical Elements, Bolts and Nuts,
Bolts, used in through holes with mating nut, are shown with ...
>
> >Strange but true.
>
> How "true" that is depends upon to which group of semantics you subscribe.
> In the inch system, machinists often refer to bolts small enough to be
> called out by number as "machine screws". If they are 1/4-inch or larger,
> and are called out by fractional size, they are "bolts".
It is largely a question of semantics as you say, most people refer to them as
you stated. However, machine screws can be found in sizes up to at least 3/4"
and some carriage bolts come in No. 10, there is overlap.
What differentiates a machine screw from a cap screw or bolt is the length of
thread. on machine screws up to 2" long complete threads extend to within two
treads of the bearing surface of the head; long screws have a minimum complete
thread length of 1/3/4". For screws and bolts (coarse thread) the minimum
thread lenght is 2D + 1/4" or 1/2 the lenght, whichever is greater.
Carriage bolts, elevator bolts, plow bolts, track bolts, etc. are always bolts,
that's because you have to use a nut, you can't tighten the head.
Can you tell I've recently been studying for my Industrial Millwright exam? :-)
Burl Vibert
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