wrench ends are generally oriented at an angle of around 15 degrees
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: wrench ends are generally oriented at an angle of around 15 degrees (with correction)
: wrench ends are generally oriented at an angle of around 15 degrees -- sanjeev_onearth	Post Reply	Top of thread	Forum

Posted by: randykimball ® 07/02/2008, 23:33:56 Author Profile eMail author Edit

(See correction below) The answer you have furnished is correct. Let me see if I can better explain the reason. Let's pretend you have a bolt with a hex head that you must remove. This bolt is between two vertical members in such a way that you can not get to it with a socket ratchet. You must use an open ended wrench and you will only get about twenty some degrees of swing. By flipping the wrench you finally get it to fit and your first twist is only about five degrees before the other end of the wrench crashes into one of the vertical members. Now you can flip the wrench and get a fresh bite on the head with the handle end of the wrench almost striking the other vertical member. Each twist of the wrench only acquires you about 20° of travel and then you again and again flip the wrench. You could never have done this with a wrench having no offset. After your first twist you would be done. This is not an uncommon occurance. ..... Why 15°? .... 360 divided by 15 is 24. You have 24 combinations of wrench positions to work with. Now couple this to the 6 sides of a hex bolt head. That is a flat every 60 degrees. Again, 15° makes the ideal offset and made it possible to accomplish the above scenerio. How many caught the mistake.... ??? Thank you Ron for the compliment... but I need to set the record right... .............CORRECTION............. As we have to train ourselves not to do, I included data in my explaination above that has nothing to do with the possible combinations an offset open ended wrench can be used in. The 360 has nothing to do with the problem other than the fact that there are 360° in a circle and we are talking about degrees. The bolt head has 6 flats at 60°. The wrench has 15° offset, this is the correct part. If the wrench had no offset you would only get to work in locations that afforded you just over 60° of rotation. With the offset at 15° this allows you to set the wrench at either the +15° or the -15° position which means you can work in locations that afford you half as much room. This gives us 12 possible combinations not 24. Now, why 15°? 2 x 15 = 30° ... half of the 60°. It has to add up to 30° which is exactly half of the 60° hex positions, or we would have 6 small segments and 6 large segments when we mated the wrench to the flats. This would trap us after the first swing of the wrench in a location with just a little over 30° of movement. So.. in order to make the answer correct I should also ammend the distances between the vertical members to allow for just over a 30° swing of the wrench. Below a 30° area to swing the tool the wrench is of little use. .... I am leaving my mistake in the post to be seen as an example of how we should be careful with our chosen data.... this being a time in which no harm to any thing other than my pride is at stake.. as we all know there are times when such a mistake could cost lives. EDITED IT ON July, 6, 2008 As Zek and I have provided examples, mistakes happen to all of us. One of my pet peeves is when engineers think they are too good to admit mistakes. While it is true that engineers are expected to catch their mistakes in situations in which serious accidents or expensive losses could occur, and should use proper check and re-check methods to avoid them, we do make mistakes. I have worked with engineers in my past whom refused to admit mistakes. In every case, it is my opinion that those engineers suffered from self confidence and were no where near the quality of engineers they pretended or thought to be. This is not to say that Zek, Kelly, myself, and others think we are "all that" just because we admitt mistakes, quite the opposite, we realize that we are human. When I seek the advice of an engineer with more skills in an area, for consult, I seek out one with the confidence to admitt mistakes and work with me on a human level. It is times like these when I believe we are making some small contribution and impact on the future engineering world. I believe many here will agree that this tiny hope is one more reason why we frequent this forum. GOOD STUFF, guys !!!! The worst suggestion of your lifetime may be the catalyst to the grandest idea of the century, never let suggestions go unsaid nor fail to listen to them. Modified by randykimball at Sun, Jul 06, 2008, 08:45:08

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: : wrench ends are generally oriented at an angle of around 15 degrees (with correction)
: : wrench ends are generally oriented at an angle of around 15 degrees (with correction) -- randykimball	Post Reply	Top of thread	Forum

Posted by: zekeman ® 07/04/2008, 23:20:23 Author Profile eMail author Edit

Randy, With all due respect, I believe that offset wrenches are offset 30 deg, not 15 so that one swing of the wrench is 60 degrees which brings the next flat of the hexagonal nut to the same location; and then the wrench is turned around to acquire the flat allowing the handle of the wrench to effectively rotate opposite 60 degrees for the next cycle.

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: : : wrench ends are generally oriented at an angle of around 15 degrees (with correction)
: : : wrench ends are generally oriented at an angle of around 15 degrees (with correction) -- zekeman	Post Reply	Top of thread	Forum

Posted by: Kelly Bramble ® 07/05/2008, 11:25:08 Author Profile eMail author Edit

Check out Open End Wrench Data /general_engineering/open-end-wrench_clearance.htm SAE designated the wrench angle as 15 degrees when the standard was created, however when looking at the second graphic they could have designated the angle as 30 degrees.

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: : : wrench ends are generally oriented at an angle of around 15 degrees (with correction)
: : : wrench ends are generally oriented at an angle of around 15 degrees (with correction) -- zekeman	Post Reply	Top of thread	Forum

Posted by: randykimball ® 07/05/2008, 00:23:01 Author Profile eMail author Edit

With equal due respect, ... All my wrenches are offset 15°. I went and rechecked with a protractor. The worst suggestion of your lifetime may be the catalyst to the grandest idea of the century, never let suggestions go unsaid nor fail to listen to them.

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: : : : wrench ends are generally oriented at an angle of around 15 degrees (with correction)
: : : : wrench ends are generally oriented at an angle of around 15 degrees (with correction) -- randykimball	Post Reply	Top of thread	Forum

Posted by: zekeman ® 07/05/2008, 11:35:25 Author Profile eMail author Edit

Randy, My turn for eating crow. You are absolutely right. I hadn't given this much thought. Keep up your good work. It is appreciated

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: : : : : wrench ends are generally oriented at an angle of around 15 degrees (with correction)
: : : : : wrench ends are generally oriented at an angle of around 15 degrees (with correction) -- zekeman	Post Reply	Top of thread	Forum

Posted by: randykimball ® 07/06/2008, 08:24:44 Author Profile eMail author Edit

Kelly, Good stuff.. Zek, Hey, it is good for us to eat crow once in a while... It keeps us realistic and humble. "Real men eat crow!"...... REALLY.... I think much more of men (AND women) who have the self confidence, courage, and intelligence to bow to mistakes openly. Many engineers would have taken the "cop out" by saying they were right because the opening is oriented to accept the hex head of the bolt at 30° across the points. Does crow taste better than shoe leather? If so, I may switch my main food group. The worst suggestion of your lifetime may be the catalyst to the grandest idea of the century, never let suggestions go unsaid nor fail to listen to them. Modified by randykimball at Sun, Jul 06, 2008, 15:20:46

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: : : : : : wrench ends are generally oriented at an angle of around 15 degrees (with correction)
: : : : : : wrench ends are generally oriented at an angle of around 15 degrees (with correction) -- randykimball	Post Reply	Top of thread	Forum

Posted by: zekeman ® 07/06/2008, 10:38:20 Author Profile eMail author Edit

Randy, Thanks for your kind words. I hate eating crow but one must bow to the truth, even in engineering. I learn a lot from my mistakes.

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: : wrench ends are generally oriented at an angle of around 15 degrees
: : wrench ends are generally oriented at an angle of around 15 degrees (with correction) -- randykimball	Post Reply	Top of thread	Forum

Posted by: CCR5600Design ® 07/03/2008, 12:04:59 Author Profile eMail author Edit

Randy, That is an excellent explanation of the orientation a typical open-ended wrench. Would you care to elaborate as to why a garden variety "crow's foot" wrench does not have this 15 degree orientation? That one has always made me curious... Ron

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: : : wrench ends are generally oriented at an angle of around 15 degrees
: : : wrench ends are generally oriented at an angle of around 15 degrees -- CCR5600Design	Post Reply	Top of thread	Forum

Posted by: randykimball ® 07/03/2008, 12:13:36 Author Profile eMail author Edit

I have no idea... also, of the same thread, .... an Allen wrench (hex key wrench) is not offset. I suspect the crow's wrench is not as expected to be used in tight locations. As for the Allen wrench, ... there have been many times I've made good use of my navy acquired language because they are not offset. Although, I can see the manufacturing problem with the Allen wrench aspect. I've been known to twist two allen wrenches, one left and one right and use them with a third that is in original condition for a difficult location. Of interest, I'm told that you can see the evolution of the offset (both angular and height) in the old Model A wrench sets provided to owners. The worst suggestion of your lifetime may be the catalyst to the grandest idea of the century, never let suggestions go unsaid nor fail to listen to them. Modified by randykimball at Thu, Jul 03, 2008, 12:21:53

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: : : : wrench ends are generally oriented at an angle of around 15 degrees
: : : : wrench ends are generally oriented at an angle of around 15 degrees -- randykimball	Post Reply	Top of thread	Forum

Posted by: sanjeev_onearth ® 07/03/2008, 15:10:07 Author Profile eMail author Edit

Randy, Pozidriv (supadriv) and Philips (crosshead)screws and drivers look same to me as well, any explainations?? Sanjeev

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: : : : wrench ends are generally oriented at an angle of around 15 degrees
: : : : wrench ends are generally oriented at an angle of around 15 degrees -- randykimball	Post Reply	Top of thread	Forum

Posted by: CCR5600Design ® 07/03/2008, 14:36:44 Author Profile eMail author Edit

Randy, While on this subject of tools and why they are designed as they are, I have never been given a good answer as to what the difference is between a "posi-drive" screwdriver and a plain ol' phillips screw driver. To me, they look the same, although both tools were well used. Any insight on this? Ron

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: : : : : wrench ends are generally oriented at an angle of around 15 degrees
: : : : : wrench ends are generally oriented at an angle of around 15 degrees -- CCR5600Design	Post Reply	Top of thread	Forum

Posted by: randykimball ® 07/03/2008, 15:26:47 Author Profile eMail author Edit

Not a clue.... guessing a patent involving the names. One interesting thing I have noticed.... often similar name differeces simply come from "down under". The worst suggestion of your lifetime may be the catalyst to the grandest idea of the century, never let suggestions go unsaid nor fail to listen to them.

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: : : : : : wrench ends are generally oriented at an angle of around 15 degrees
: : : : : : wrench ends are generally oriented at an angle of around 15 degrees -- randykimball	Post Reply	Top of thread	Forum

Posted by: Kelly Bramble ® 07/03/2008, 19:12:45 Author Profile eMail author Edit

Thats right Randy, the name is "POZIDRIV" and is a registered trademark of Snapon Tools. The POZIDRIV tool line is a collection of tools drive ends such as; straight edge, phillips, star drives and more. Good stiff BTW.

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