Re: Bolt shear strength

An unlikely but helpful resource for this type of information is a small
book published by Bowman Fasteners called "Fastener Facts". I'm quite sure
they deal at length about shear strength. How the fastener is used also
needs to be considered. A properly torqued through bolt with nut behaves
differently than a bolt threaded into a hole. Industrial Fastener
Institute's "Fastener Standards" also has a section on shear applications.

The bolt vs screw debate is primarily a personal preference thing in my
opinion. You can find a definitive source to support almost position. When
in doubt, I'm frequently inclined to defer to Machinery's Handbook, but in
this case I'd use IFI's "Fastener Standards" for questions on definitions as
they have taken the lead in this area. I'll bet that Machinery's Handbook
will agree with IFI as Machinery's Handbook is just a compilation of data
from other sources.

Jon Juhlin

"Mark Harrand" <[EMAIL PROTECTED]> wrote in message
news:[EMAIL PROTECTED]
> A bolt is an externally threaded fastener designed for insertion through
> holes in assembled parts, and is normally intended to be tightened or
> released by torquing a nut.
>
> A screw is an externally threaded fastener capable of being inserted into
> holes in assembled parts, of mating with preformed internal threads, or
> forming its own thread and of being tightened or released by torquing its
> head.
>
>      --Machinery's Handbook, 22nd edition, Oberg, Jones & Horton (any
typos
> mine)
>
> There's more, but you get the picture. I don't think the shank matters.
>
> MH
>
> "[EMAIL PROTECTED] (formerly)" <[EMAIL PROTECTED]> wrote in message
> news:[EMAIL PROTECTED]
> > Dear Jeff Finlayson:
> >
> > "Jeff Finlayson" <[EMAIL PROTECTED]> wrote in message
> > news:[EMAIL PROTECTED]
> > > Hobdbcgv wrote:
> > >
> > > >>> A screw by definition is fully threaded.  A bolt has a shank on
it.
> > > Yea probably not a general definition really.
> > >
> > > > I think a screw is defined as being held by threading into a
material,
> > while a
> > > > bolt is defined as being held by a nut (ref Shigley, among others) .
> > >
> > > I can't find anything in Shigley's ME Design book that agrees with
that.
> > It
> > > may be buried somewhere.  The book uses the terms screw and bolt
almost
> > > interchangeably.
> > >
> > > A power/lead screw is fully threaded and is referred to as a screw not
> > bolt.
> > > Aerospace fastener specs (NAS, MS, ..) refer to fasteners with
> unthreaded
> > > shanks as bolts and fully threaded fasteners as screws.
> >
> > This is what the trades use for a definition too.
> >
> > > > I.e., look at it as a definition of application of a threaded headed
> > device,
> > > > rather than the name of the device itself, e.g., a 1/4-20 2" hex
head
> > can be
> > > > used either as a bolt or a screw.
> > > >
> > > > Flat head wood screws, for example, all have unthreaded shanks.
> > >
> > > Probably an exception.  They would not be referred to as bolts since
> > > they have pointed tips.
> >
> > In those cases, the unthreaded portion is to provide a bearing surface
> when
> > joining two or more "boards".
> >
> > Another exception is a carriage bolt, which is almost always threaded
all
> > the way up, and is always called a carriage bolt.
> >
> > All rules have exceptions, probably even this one!  ;>}
> >
> > David A. Smith
> >
> >
>
>