Metalworking (rec.crafts.metalworking) Discuss various aspects of working with metal, such as machining, welding, metal joining, screwing, casting, hardening/tempering, blacksmithing/forging, spinning and hammer work, sheet metal work.

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  #1   Report Post  
Bryan
 
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Default Why are hex head bolts hex rather than Octagonal (or square?)

Whilst thinking about another problem, I find myself wondering, "why is
it that bolts have hex heads rather than octagonal or some other
number?"

Is there some wisdom about the history of this?

bmw

  #2   Report Post  
DoN. Nichols
 
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According to Bryan :
Whilst thinking about another problem, I find myself wondering, "why is
it that bolts have hex heads rather than octagonal or some other
number?"


Well ... for a few guesses:


1) Hex has more surface area on the flats, and is harder to round
off with a wrench.

2) Hex uses less material relative to the major diameter than
octagonal.

3) Hex stock stores more compactly. No waste space.

4) It takes fewer cuts to machine the flats, if not working
from stock already that shape. This saves machining time.

5) Hex is easy to grip with a three-jaw chuck, which is the best
for quick gripping of round stock. Octagonal would require a
universal 4-jaw -- which does exist, but which is uncommon, and
a slight irregularity with 4 jaws means that one will not be
gripping firmly.

Is there some wisdom about the history of this?


I'll leave others to deal with the history. I've just listed
the advantages to hex which come to mind readily. Besides -- it is time
to go to bed. :-)

Enjoy,
DoN.
--
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---
  #3   Report Post  
PrecisionMachinisT
 
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"Bryan" wrote in message
ups.com...
Whilst thinking about another problem, I find myself wondering, "why is
it that bolts have hex heads rather than octagonal or some other
number?"

Is there some wisdom about the history of this?


First off, ( and most obvious ) if it had anything other than 6 faces,
wouldn't make much sense at all to call it a "hex"......


Eight points tend to strip too easily...

And at some point, needing to tighten fully to 90 degres in order to be able
to reposition a wrench was apparently too much for design engineers...


I kinda like the NAS style aircraft fasteners, personally.....

--

SVL




  #4   Report Post  
Don Foreman
 
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On 19 Sep 2005 22:07:37 -0700, "Bryan" wrote:

Whilst thinking about another problem, I find myself wondering, "why is
it that bolts have hex heads rather than octagonal or some other
number?"

Is there some wisdom about the history of this?

bmw


A guess: bolt heads were once square, requiring 90 degrees of
rotation before a simple wrench could be repositioned to grab another
bite. Machinery got more complex, spaces got tighter and access more
limited, hence hex requiring only 60 degrees of rotation between
bites before robust ratchet wrenches were available.

It's easier to strip the corners off a hex than a square, but the hex
is usually strong enough to shear a bolt before the corners fail.



  #5   Report Post  
Don Foreman
 
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On Mon, 19 Sep 2005 23:35:31 -0700, "PrecisionMachinisT"
wrote:

And at some point, needing to tighten fully to 90 degres in order to be able
to reposition a wrench was apparently too much for design engineers...

Design engineers usually do what marketing directs because marketing
usually controls engineering funding.

I kinda like the NAS style aircraft fasteners, personally.....


Who do you suppose designed those fasteners? Might it have been
design engineers allowed to design for peformance?



  #6   Report Post  
Nick Müller
 
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Bryan wrote:

Whilst thinking about another problem, I find myself wondering, "why is
it that bolts have hex heads rather than octagonal or some other
number?"


Here is my answer:
Hex once were square (and not called hex :-). They used to much space
(distance bolt hole - housing). The next step would have been a
pentagon. One one huge pentagon was built (some in there are nuts), but
a pentagon is not something you could grap with a wrench. So a hex, the
next step, is the closest to a circle (least assembling space) and the
nearest to a square (best contact surface for a wrench).

HTH,
Nick
--
Motor Modelle // Engine Models
http://www.motor-manufaktur.de
  #7   Report Post  
Harold and Susan Vordos
 
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"Don Foreman" wrote in message
...
On 19 Sep 2005 22:07:37 -0700, "Bryan" wrote:

Whilst thinking about another problem, I find myself wondering, "why is
it that bolts have hex heads rather than octagonal or some other
number?"

Is there some wisdom about the history of this?

bmw


A guess: bolt heads were once square, requiring 90 degrees of
rotation before a simple wrench could be repositioned to grab another
bite. Machinery got more complex, spaces got tighter and access more
limited, hence hex requiring only 60 degrees of rotation between
bites before robust ratchet wrenches were available.


Note that the typical open end wrench is angled---so by flipping the wrench
over you can make small adjustments in confined quarters. It would not work
as well with a square head.

Harold



  #8   Report Post  
jim rozen
 
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In article , DoN. Nichols says...

1) Hex has more surface area on the flats, and is harder to round
off with a wrench.

2) Hex uses less material relative to the major diameter than
octagonal.

3) Hex stock stores more compactly. No waste space.

4) It takes fewer cuts to machine the flats, if not working
from stock already that shape. This saves machining time.

5) Hex is easy to grip with a three-jaw chuck, which is the best
for quick gripping of round stock. Octagonal would require a
universal 4-jaw -- which does exist, but which is uncommon, and
a slight irregularity with 4 jaws means that one will not be
gripping firmly.


6) Because wrenches are harder than the fasteners, it's possible to
double the number of points on the wrench - from 6, to 12. 12 is
bigger than 8, and it's probably not possible to double from 8 to 12,
given the common metalurgy.

So by chosing hex heads, it increases the number of index points on the
fastener from 8 to 12, over octagonal.

Jim


--
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please reply to:
JRR(zero) at pkmfgvm4 (dot) vnet (dot) ibm (dot) com
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  #9   Report Post  
 
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"Bryan" wrote:

Whilst thinking about another problem, I find myself wondering, "why is
it that bolts have hex heads rather than octagonal or some other
number?"

Is there some wisdom about the history of this?

bmw


Well, an even number of sides are needed to allow for open end
wrenches leaving out 3,5,7,...

4 is the first number that works but has a fairly large diameter and
only 4 wrenching positions. Worked great for farm implements. Still
a good choice at times. Still used.

6 is next. Must have been a good compromise on diameter relative to
bolt shank, 6 wrenching positions, and works with 12pt bo and sockets
to give 12 wrenching positions.

8 would have to be closer tolerance on bolt head and wrench. Likely
would not work well with open end wrenches or polish calipers.

Wes

--
The Constitution wasn't perfect but it sure beats
what we have now.
  #12   Report Post  
Robert Swinney
 
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Once I made a "hex" head bolt and nut from 2 inch brass and left it on my
desk at work as a paper weight. The bolt head was not really hex but had
seven faces rather than 6 and the thread was left-handed. Visitors would
invariably pick it up and play with it while talking or waiting for me to
get off the phone. Everyone would notice the left-hand thread, but almost
no one picked up on the seven-sided head until I asked, "Do you see anything
else strange?"

Bob Swinney
wrote in message
...
"Bryan" wrote:

Whilst thinking about another problem, I find myself wondering, "why is
it that bolts have hex heads rather than octagonal or some other
number?"

Is there some wisdom about the history of this?

bmw


Well, an even number of sides are needed to allow for open end
wrenches leaving out 3,5,7,...

4 is the first number that works but has a fairly large diameter and
only 4 wrenching positions. Worked great for farm implements. Still
a good choice at times. Still used.

6 is next. Must have been a good compromise on diameter relative to
bolt shank, 6 wrenching positions, and works with 12pt bo and sockets
to give 12 wrenching positions.

8 would have to be closer tolerance on bolt head and wrench. Likely
would not work well with open end wrenches or polish calipers.

Wes

--
The Constitution wasn't perfect but it sure beats
what we have now.



  #13   Report Post  
John Martin
 
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Bryan wrote:
Whilst thinking about another problem, I find myself wondering, "why is
it that bolts have hex heads rather than octagonal or some other
number?"

Is there some wisdom about the history of this?

bmw


Maybe because you can lay out a hexagon on a circle with just a compass
and straightedge? The people who first came up with hex head screws
didn't have CNC machines...

John Martin

  #14   Report Post  
Cliff
 
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On Tue, 20 Sep 2005 09:24:21 -0400, wrote:

polish calipers


Older micrometers?
--
Cliff
  #15   Report Post  
Jeff Wisnia
 
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jim rozen wrote:
In article , DoN. Nichols says...


1) Hex has more surface area on the flats, and is harder to round
off with a wrench.

2) Hex uses less material relative to the major diameter than
octagonal.

3) Hex stock stores more compactly. No waste space.

4) It takes fewer cuts to machine the flats, if not working
from stock already that shape. This saves machining time.

5) Hex is easy to grip with a three-jaw chuck, which is the best
for quick gripping of round stock. Octagonal would require a
universal 4-jaw -- which does exist, but which is uncommon, and
a slight irregularity with 4 jaws means that one will not be
gripping firmly.



6) Because wrenches are harder than the fasteners, it's possible to
double the number of points on the wrench - from 6, to 12. 12 is
bigger than 8, and it's probably not possible to double from 8 to 12,
given the common metalurgy.


Double from 8 to 12?

I think not.

But it surely could have been accomplished with Reganomics.... :-)


Jeff

--
Jeffry Wisnia

(W1BSV + Brass Rat '57 EE)

"Truth exists; only falsehood has to be invented."


  #16   Report Post  
Cliff
 
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On 20 Sep 2005 09:29:47 -0700, "John Martin"
wrote:

Maybe because you can lay out a hexagon on a circle with just a compass
and straightedge? The people who first came up with hex head screws
didn't have CNC machines...


But could they trisect the angles?

Will this morph into another bible "wisdom" thread?
--
Cliff
  #17   Report Post  
Curly Surmudgeon
 
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On Tue, 20 Sep 2005 13:03:44 -0400, Cliff wrote:

On 20 Sep 2005 09:29:47 -0700, "John Martin"
wrote:

Maybe because you can lay out a hexagon on a circle with just a compass
and straightedge?


Doesn't work, you still wind up with an unused (0.14159 * radius)
circumference.

The people who first came up with hex head screws
didn't have CNC machines...


But could they trisect the angles?

Will this morph into another bible "wisdom" thread?


A hexagon is a natural shape, unlike squares, octagons, etc. Ever seen a
beehive? A hexagon is stronger than a square or octagon and less likely
to round off than an octagon.

-- Regards, Curly
------------------------------------------------------------------------
http://curlysurmudgeon.com/blog/
------------------------------------------------------------------------

  #18   Report Post  
jim rozen
 
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In article , Curly Surmudgeon says...

A hexagon is a natural shape,


Don't see many hexagonal rocks. Besides, I know lots of
people with square heads...

:^)

Jim


--
==================================================
please reply to:
JRR(zero) at pkmfgvm4 (dot) vnet (dot) ibm (dot) com
==================================================
  #19   Report Post  
 
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misc.survivalism removed from distribution.

Curly Surmudgeon wrote:
On Tue, 20 Sep 2005 13:03:44 -0400, Cliff wrote:

On 20 Sep 2005 09:29:47 -0700, "John Martin"
wrote:

Maybe because you can lay out a hexagon on a circle with just a compass
and straightedge?


Doesn't work, you still wind up with an unused (0.14159 * radius)
circumference.


Yes it does. The segments that comprise the circumfrence of
an inscribed hexagon are chords, not arcs. Each one is
(0.14159 * radius)/6 shorter than the arc they span.

Only six points of the circle lie on the hexagon, at the six
corners.

Thanks for making me think.

--

FF

  #20   Report Post  
Dave Hinz
 
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On 20 Sep 2005 10:37:55 -0700, jim rozen wrote:
In article , Curly Surmudgeon says...

A hexagon is a natural shape,


Don't see many hexagonal rocks. Besides, I know lots of
people with square heads...


Um, beehives?



  #21   Report Post  
Leo Lichtman
 
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"Jeff Wisnia" wrote: Double from 8 to 12? (clip)
^^^^^^^^^^^^^
Half of 8 is 4. 8 + 4 = 12. Do you listen to the "third half" of the Car
Talk show?


  #22   Report Post  
Leo Lichtman
 
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"Cliff" wrote: (clip) Will this morph into another bible "wisdom" thread?
(clip)
"Curly Surmudgeon" wrote" (clip) A hexagon is a natural shape (clip)
^^^^^^^^^^^^^^^^
Then how come haloes aren't hexagonal?


  #23   Report Post  
Jeff Wisnia
 
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Leo Lichtman wrote:
"Jeff Wisnia" wrote: Double from 8 to 12? (clip)
^^^^^^^^^^^^^
Half of 8 is 4. 8 + 4 = 12. Do you listen to the "third half" of the Car
Talk show?




No, but I think I got this week's Puzzler nailed....

Leave the radiator cap loose. And stuff a large sized Tootsie Roll
through the slit in the heater hose. IIRC those candies were about 3/4"
dia x 6" long.

Jeff

--
Jeffry Wisnia

(W1BSV + Brass Rat '57 EE)

"Truth exists; only falsehood has to be invented."
  #24   Report Post  
Charles Spitzer
 
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"jim rozen" wrote in message
...
In article , Curly Surmudgeon says...

A hexagon is a natural shape,


Don't see many hexagonal rocks. Besides, I know lots of
people with square heads...

:^)

Jim


at the crystalline leve, there may be a lot of hex sided rocks.


  #25   Report Post  
mike
 
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jim rozen wrote in
:

In article , Curly Surmudgeon

says...

A hexagon is a natural shape,


Don't see many hexagonal rocks. Besides, I know lots of
people with square heads...

:^)

Jim



Google the 'giants causeway'..


  #26   Report Post  
 
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"John Martin" wrote:
If the heads were Octagonal, they'd be called Octangonal bolts. Similarly
square heads are called Square head bolts. It follows that hex head bolts have
hexagonal heads.

Sorry, I couldn't resist.
Best


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  #29   Report Post  
Will
 
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On Tue, 20 Sep 2005 13:01:54 -0400, Cliff wrote:

On Tue, 20 Sep 2005 09:24:21 -0400, wrote:

polish calipers


Older micrometers?


Adjustable wrench

Will
  #30   Report Post  
 
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Leo Lichtman wrote:
"Cliff" wrote: (clip) Will this morph into another bible "wisdom" thread?
(clip)
"Curly Surmudgeon" wrote" (clip) A hexagon is a natural shape (clip)
^^^^^^^^^^^^^^^^
Then how come haloes aren't hexagonal?


1) A hexagon isn;t th eonly natural shape.

2) Since when are haloes natural?

--

FF



  #31   Report Post  
Will
 
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On Tue, 20 Sep 2005 18:05:13 GMT, "Leo Lichtman"
wrote:


"Cliff" wrote: (clip) Will this morph into another bible "wisdom" thread?
(clip)
"Curly Surmudgeon" wrote" (clip) A hexagon is a natural shape (clip)
^^^^^^^^^^^^^^^^
Then how come haloes aren't hexagonal?

Because halos are a corona effect.
  #32   Report Post  
Cliff
 
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On Tue, 20 Sep 2005 19:20:24 GMT, Will
wrote:

On Tue, 20 Sep 2005 18:05:13 GMT, "Leo Lichtman"
wrote:


"Cliff" wrote: (clip) Will this morph into another bible "wisdom" thread?
(clip)
"Curly Surmudgeon" wrote" (clip) A hexagon is a natural shape (clip)
^^^^^^^^^^^^^^^^
Then how come haloes aren't hexagonal?

Because halos are a corona effect.


So are gummer's cheap cigars.
--
Cliff
  #33   Report Post  
 
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So they fit six and twelve point sockets... Why else ;-)

Think of the expense of everyone having to buy five-sided sockets, or
some other goofy configuration.

  #34   Report Post  
Leo Lichtman
 
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wrote in message ...
"John Martin" wrote: If the heads were Octagonal, they'd be called
Octangonal bolts. Similarly square heads are called Square head bolts. It
follows that hex head bolts have hexagonal heads. (clip)

^^^^^^^^^^^^^^^^
Should be named circular bolts, since they were named using circular logic.


  #35   Report Post  
Lew Hartswick
 
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wws wrote:
I hope GM or Ford doesn't monitor this group.
They will start using nonasymetrical pentagonal fasteners on everything.

--------------

I take it you mean "regular" then. (double negatives and all that stuff)
...lew...


  #36   Report Post  
Lew Hartswick
 
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Robert Swinney wrote:

Once I made a "hex" head bolt and nut from 2 inch brass and left it on my
desk at work as a paper weight. The bolt head was not really hex but had
seven faces rather than 6 and the thread was left-handed. Visitors would
invariably pick it up and play with it while talking or waiting for me to
get off the phone. Everyone would notice the left-hand thread, but almost
no one picked up on the seven-sided head until I asked, "Do you see anything
else strange?"

Bob Swinney


Just the bolt or both? Sound like a neet thing to do. I'll have to try it.
...lew...
  #37   Report Post  
Lew Hartswick
 
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jim rozen wrote:

In article , Curly Surmudgeon says...

A hexagon is a natural shape,


Don't see many hexagonal rocks. Besides, I know lots of
people with square heads...

:^)

Jim


Yes but are they "natural" ? I suspect they are "liberals".
DUCKING and running. :-)
...lew...
  #38   Report Post  
Lew Hartswick
 
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jim rozen wrote:

Don't see many hexagonal rocks.

:^)

Jim


PS. I think columnar basalt is hexagonal, or at least some
of it.
...lew...
  #39   Report Post  
jim rozen
 
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In article et, Lew Hartswick
says...

PS. I think columnar basalt is hexagonal, or at least some
of it.


Possibly, but a *very* close inspection of the
NY/NJ Pallisades does not show any hexagons. Maybe
the crystallographic form is hexagonal, but it
does not show up in the cliffs anywhere.

Jim


--
==================================================
please reply to:
JRR(zero) at pkmfgvm4 (dot) vnet (dot) ibm (dot) com
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  #40   Report Post  
Don Bruder
 
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In article et,
Lew Hartswick wrote:

jim rozen wrote:

Don't see many hexagonal rocks.

:^)

Jim


PS. I think columnar basalt is hexagonal, or at least some
of it.
...lew...


ALL naturally occurring quartz crystals are hexagonal in cross-section...

--
Don Bruder - - New Email policy in effect as of Feb. 21, 2004.
Short form: I'm trashing EVERY E-mail that doesn't contain a password in the
subject unless it comes from a "whitelisted" (pre-approved by me) address.
See http://www.sonic.net/~dakidd/main/contact.html for full details.
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