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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 |
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 --- |
"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 |
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. |
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? |
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 |
"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 |
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 -- ================================================== please reply to: JRR(zero) at pkmfgvm4 (dot) vnet (dot) ibm (dot) com ================================================== |
"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. |
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Brian Lawson wrote:
On Tue, 20 Sep 2005 09:31:47 +0200, (Nick Müller) wrote: 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. Pentagons are used here as the utility companies standard for shut-offs, especially below grade. Presumably to stop the un-authorized actuation of these valves, either on or off. Brian Lawson. Bothwell, Ontario. I hope GM or Ford doesn't monitor this group. They will start using nonasymetrical pentagonal fasteners on everything. |
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. |
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 |
On Tue, 20 Sep 2005 09:24:21 -0400, wrote:
polish calipers Older micrometers? -- Cliff |
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." |
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 |
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/ ------------------------------------------------------------------------ |
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 ================================================== |
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 |
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? |
"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? |
"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? |
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." |
"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. |
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'.. |
"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 ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups ----= East and West-Coast Server Farms - Total Privacy via Encryption =---- |
Cliff wrote:
On Tue, 20 Sep 2005 09:24:21 -0400, wrote: polish calipers Older micrometers? I never heard that term before either, but I'm guessing it refers to an adjustable open end wrench, i.e. a "Crescent wrench." Which, except for its straight handle, is quite similar in design to what some of us old farts remember as a "Wescott". http://www.westcottsociety.com/Archi...ems/wrench.htm Jeff -- Jeffry Wisnia (W1BSV + Brass Rat '57 EE) "Truth exists; only falsehood has to be invented." |
On Tue, 20 Sep 2005 14:54:57 -0400, Jeff Wisnia
wrote: Cliff wrote: On Tue, 20 Sep 2005 09:24:21 -0400, wrote: polish calipers Older micrometers? I never heard that term before either, but I'm guessing it refers to an adjustable open end wrench, i.e. a "Crescent wrench." Which, except for its straight handle, is quite similar in design to what some of us old farts remember as a "Wescott". http://www.westcottsociety.com/Archi...ems/wrench.htm That looks a bit like a knuckle-buster. Worse than a monkey wrench. -- Cliff |
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 |
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 |
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. |
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 |
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. |
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. |
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... |
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... |
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... |
jim rozen wrote:
Don't see many hexagonal rocks. :^) Jim PS. I think columnar basalt is hexagonal, or at least some of it. ...lew... |
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 ================================================== |
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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