Why 82 Degrees?
Gerald Masgai
Just so you won't spend another night worrying about things like this here
is where you can find your answer.
http://www.normas.com/ASME/ASME/asmefasc.htm
(The following text is quoted from the above site.)
B18.6.1-1981(R1991)
WOOD SCREWS (INCH SERIES)
This standard covers the complete general and dimensional data for the
various types of slotted and recessed head wood screws recognized as
American National Standard. Also included are appendixes which provide
specifications and instructions for penetration gaging and wobble gaging of
recessed head screws; documentation for screw head types relegated to
non-preferred status; and formulas on which dimensional data are based. It
shall be understood, however, that where questions arise concerning
acceptance of product, the dimensions given in the tables shall govern over
recalculation by formula. The inclusion of dimensional data in this standard
is not intended to imply that all of the products described are stock
production sizes. Consumers should consult with manufacturers concerning the
availability of products.
When you have finished digesting this rather somber tome, you may want to
know what the US Government has to say on the subject.
Point your browser to
http://www.customs.treas.gov/imp-exp1/comply/bolts2.htm
everything you ever wanted to know about screws and bolts is discussed here.
Just don't blame me for finding this bit of trivia, you asked for it.
--
Best of luck in your endeavors,
Gerald Masgai
Reply to: g-masgai@ix,netcom.com
Notes From My Shop: http://www.netcom.com/~g-masgai/shop/index.html
Akilli wrote in message <19981005213739...@ng02.aol.com>...
>
>Greetings,
> Here is a question which is guaranteed to enrich almost nobody's
>life; but why are screws, at least in America countersunk at 82 degrees? I
>understand that European screws are countersunk at 90 degrees; a
comprehensible
>figure at least. I imagine, that it was either a purely arbitrary
convention,
>or the result of an elaborate calculation by a mechanical engineer trying
to
>minimize some quantity or other.
> Any accredited screw historians out there?
>
> Much
Obliged,
> Ethan
Gross
>
Akilli
Frank Shapiro
meant to replace the nail. The old square nails once used as well were
not 90 degrees but were indeed on average 82 degrees, and the manufacturer
of screws wanted to fill the same hole and as such maintained the angle.
Now why were nails 82 well that comes from how they were made, they were
cut pieces of metal cut with a chisel and placed in an anvil (for making
nails) and the top was hammered to give us the flat nail, and mushroom
head. The Anvil had an 82 degree inpression for this, although not all
nails followed this convention, just the majority. Now why did the
anvil have that angle, this goes back to the ancient greeks, who when
making chariots and eventially banding the wheels, were avid smokers, at
that time, there were no ashtrays, so the original blacksmiths in those
days drilled their anvil and placed an angle on to it to hold there
cigarette. In shops where many blacksmitchs worked many holes had to be
drilled with and angle to keep the cigarette tilted, so they made a neat
little drill bit which we call a counter sink. Eventually they the tool
wore with time and the hole got smaller. In time the hole no longer held
a cigarette, and was then used to drill anvils for making nails. So there
you have it, the screw angle is based on the angle required to hold a
cigarette. By the way I have some swamp land to sell, very high quality.
--
...SPAM PROTECTION IN EFFECT....
Frank Shapiro B.Eng
Real Email is: user is shapiro_
location is yahoo.com
Akilli <aki...@aol.com> wrote in article
<19981005213739...@ng02.aol.com>...
Jon Schilling
Jon
Frank Shapiro wrote in message
<01bdf123$48b34720$fc93...@c7196.canada.cdev.com>...
Powakee
j
Jim Levie
On 10/6/98, 6:14:31 AM, "Frank Shapiro" <sp...@up.yours.com> wrote
regarding Re: Why 82 Degrees?:
Wonderful, but erronous, reasoning, the truth is far more prosaic.
Seems the poor benighted soul charged with making the first batch of
countersinks got everything all set up and turned out several hundred
before anyone noticed that he'd made a mistake in setting the angle
(naww, doesn't sound like anybody anyone of us know...). Since, there
hadn't been any point in making countersunk screws before a
countersink existed, they just started making 82deg screws and kept on
making matching countersinks.
Larry Jaques
>Where's the land? :o)
It's above the sea and beneath the sky, of course. <gd&r>
That reminds me of the story about why they started
using a 100 degree head on screws...
----------------------------------------------------------------------
* Michelangelo would have made * Web Design & Humorous T-shirts
* better time with a roller. * http://diversify.com/ljaques
----------------------------------------------------------------------
Frank Shapiro
have any countersunk screws, why is setting them called countersinking
them.
--
...SPAM PROTECTION IN EFFECT....
Frank Shapiro B.Eng
Real Email is: user is shapiro_
location is yahoo.com
Jim Levie <Jim....@dynetics.com> wrote in article
<19981007...@enigma.r1.dynetics.com>...
>>>>>>>>>>>>>>>>>> Original Message <<<<<<<<<<<<<<<<<<
----------
arkwr...@frontline.com
[...]
>That reminds me of the story about why they started
>using a 100 degree head on screws...
>
Aw, jeezus, Larry. Are you gonna start a
Monica Lewinsky thread? And just before Hallowe'en <sigh>.
How're you gonna work in the cigar ?
<GGG>
Rob Weaver
the same way she did???