Why Is It So? - Adjustable Spanner, Wrench, Shifter

Left and right-handed?

Sometimes easier to get that bit extra tightness on a bad head by pushing with the thumb as the wrench is turned - or pulling, depending on the position of the nut (usually behind the exhaust)

Somebody put the thumbscrew in backwards!!

That's easy! One is made in the northern hemisphere, the other in the southern hemisphere.

A couple of things come to mind,

Back when I was working on marine gearing we had to identify if the helix we were speaking of was a left or right hand helix. A little memory helper was to salute the gear with the left and right hand (in your mind of course, you wouldn't want the locals to think you were nuts) and if the helix was in line with the direction of the salute that was the hand of the helix.

Your photos clearly show that the threads are reversed on the "Alabama socket sets", I have been trying to imagine if you flipped the gear would the hand change, this created a huge vacuum and the mind shut down. Not interested enough to pursue it further.

When working on the submarines we used to file another slot on the moveable jaw and cut about 4 inches out of the handle and weld it back together, that way you could get at a 1 1/2" fitting buried in behind pipes.

Otha,

Flipping end for end won't change the hand of the threads. Think of right handed threaded rod - you can flip it or cut some off and it all remains right handed.

Dave

I think you've missed the point here: see post #14

The thumb-wheel remains fixed relative to the main body of the wrench: looking at the larger of the two in the picture, if you rotate the thumb-wheel clockwise (looking from the right hand side of the picture) then the moveable jaw slides to the right closing the jaws.

Now flip the spanner over sideways; rotating the thumb-wheel clockwise sill causes the moveable jaw to move to the right (as you point out), but, now the jaws are opening.

Depends which side of the Equator it was made on.
Drat missed #4, beat me to it
Del

One is metric and one is inch.

That is a typical example of reverse engineering.

The correct terminology for this wrench is "adjustable open end wrench" and the best were and still are made in the U.S.A. by Crescent Wrench Co. They are sometimes referred to as "Crescent wrenches".

Have to disagree with you on this one Ronseto (and it is all a matter of opinion I know), I call it a shifting spanner or shifter and the best were and still are made by Bahco of Sweden.

In a lot of Europe these things are just referred to as Bahcos never mind who made them. They are also the odd one out when it comes to opening and closing direction. My first Volvo had a Bahco shifter with a flattened handle that doubled as a tyre lever. Indestructible tool.

The adjustable wrench is attributed to Johann Johansson (some claim for an Englishman beating him to it but not sure) who patented it in 1891 and this forms the basis for all the Bahco's produced since then.

The Crescents that I have used are good but I do not believe they are in the same league.

Thats right, I have always known them as bahcos! Maybe the reason why they have different helix hands is that they (crescent tool co?) had to bypass a patent description.

Dutchy

"Maybe the reason why they have different helix hands is that they (crescent tool co?) had to bypass a patent description." No! Any patent lawyer who wrote the application so narrowly as to permit this to bypass it should have had his (her) license yanked, and the university at which (s)he was trained should have had ITS accreditation removed. You'd have to deliberately mess up to make such a thing invalidate a patent - "minor changes (which would be) obvious to anyone skilled in the art" are pretty much automatically covered. In any case, adjustable wrenches had been around so long by the period referenced here [1891, post #15] that such a feature would have been in the public domain: see http://www.google.com/patents?id=eLdWAAAAEBAJ&pg=PA1&source=gbs_selected_pages&cad=1#v=onepage&q=&f=false for an adjustable wrench using this principle in 1857, for example.

A good reference site for such things is Alloy Artifacts, at http://alloy-artifacts.com/index.html - but they don't seem to even list Bahco. Their history on Crescent is at http://www.alloy-artifacts.com/crescent-tool.html. See http://www.bahco.com/asp/front/index.asp?lngStructureID=1098&lngMenuID=1127 for Bahco's own history.

Seems it's not the North/South hemisphere which makes the difference - the one on the left is "Bahco" Made in Sweden, the one on the right is "Crescent Tool Co." Jamestown NY USA. - both above the Equator. Use for left/right hand thread options is not a viable reason even though there is a correct orientation for the use of these and I don't think special manufacture for left or right hand operators would be a realistic reason.

Maybe someone read the production drawing upside down?

not the North/South hemisphere ..
Ah but as you cross the Equator, you must use it behind your back, which laterally transposes the Left Right Vector interface about the vertical axis of pseudo symetry, thus introducing the correcting factor required for clockwise/ACW compensation of the sensory field.
Or whateva'
Del

I know someone will prove me wrong but looking at my stuff, anything from the US/Asia seems to have the steeper screw angle (RHS in pic) anything Euro is shallow angle.

otha nearly got it at post #5

Turn one of those wrenches over.

The arbitrary decision is not which thread the thumb screw is, but, which way the head is "biased".

Think about it another way, if you have to push your thumb "up" (towards the business end) on one side to close the jaws then you must need to pull it "down" on the other.

This one from Black & Decker overcomes the problem. My favourite is a tool I bought last year which combines the adjustable spanner & mole grip so you can lock the jaws on to the nut.

In Germany when a young man takes a job at a car maker or fab shop they usually spend 2 or 3 months with a hammer and peices of metal. They have to learn to shape it, mold it and damage it by hand. After a few months they are given small duties like handling body panels or sorting scrap metal to salvage useable material.

My point is they spend a lot of time learning how to use tools and work around metal, tools and getting to know the materails and tools they use at work. So all that time learning has produced good tool design.

I like the German designed tools but to get around Patent laws flipping the adjuster makes sense and changing the angle to save materail .

Patent laws could be the reason your look for as the difference.

Since we haven't had a "What is it?" puzzle for some time:-

http://cr4.globalspec.com/thread/43061/Photo-Challenge-What-s-This-Machine

Flip one wrench over and the threads are in the same direction. An adjustable wrench works best if you can place the non-adjustable side on the right of the nut to tighten, and to the left of the nut to loosen, and I cant help but wonder if this was in mind when these two wrenches were designed.

I thought this was an adjustable spanner???

It is more like a stereo screwdriver.

An ignoramus's questions (may lead to a reason):
Do you sometimes need to do it up tight to unfasten a worn nut?
Do you ever have to work in a tight space so that you need to use both orientations alternately?
Is it easier to tighten the jaws by pushing with your thumb than by pulling?

If so, would you want to use a matched symmetrical pair?
(that would explain why I too have spanners with different chirality in my tool-chest - though I've not yet found the need to swap tools)

P.S. Is this relevant to this week's repeat of the mirror challenge?

"...up tight to unfasten a worn nut?" Yes; sometimes worn or corroded nuts are no longer a correct fit for EITHER metric or inch-based wrenches; and damaged ones may have different widths across the flats for each pair of faces, so that it is necessary to keep switching sizes.

"...have to work in a tight space so that you need to use both orientations alternately?" Yes, just as with ordinary open-end wrenches. IF a standard wrench will fit, it is a much better choice because its head will be far smaller than the adjustable.

"Is it easier to tighten the jaws by pushing with your thumb than by pulling?" I find it so. Being right-handed, I prefer wrenches that work this way in my right hand, but a lefty using the same wrench would be at a disadvantage, just as when I can only reach a spot with the wrench in my left hand. I recall a time when I'd just spent several minutes under a car, squirming into a position where my hand went upward along the firewall and I could JUST BARELY get the wrench onto the nut by feel. I could not see the work area at all, and was in an extremely awkward position. After several failed attempts to get things lined up and the adjustment right, I asked the guy nearby, "Which way does the nut turn to tighten this wrench?" [and it was his wrench that I was using] "Oh, the regular way - just turn it like you're tightening." If I could have disentangled myself and gotten near him, he'd have gotten the worst dope-slap of his life just then. I later showed him that another of his own adjustable wrenches was opposite-handed to this one.

[To an unasked question] No, I would never buy matched pairs in order to have the right tool in hand for a particular spot, or use its mate when re-installing a nut. Nor can I imagine anyone doing so.

I suspect your view is universal, as Bahco wrenches appear to use exclusively left-hand spirals.

However, it could be significantly easier to undo a worn nut in a tight spot if you could swap wrenches. Incidentally, left/right handedness of the user is never the only feature - indeed it is irrelevant if the axis of the nut is vertical. What is important (for a given wrench) is the interaction between its orientation and the side where you place your thumb; unfortunately, if the nut is in a tight spot you will have little choice regarding the wrenche's orientation

[To an unasked question] No, I would never buy matched pairs in order to have the right tool in hand for a particular spot...

You buy tools just because you can't resist them (I know I do). I have many tools that I bought just because they looked good & that includes many sets of spanners.

Oh, I have plenty of tools that I've bought because they looked good, and multiple sets of wrenches (spanners); but I'd STILL never buy opposite-handed pairs of adjustables, not even from Crescent, Bahco, or Diamond Tool & Horseshoe Company (used to use a very well made example in large size, at a former employer). Opposite-handed pairs are just ASKING for extra effort at every use, due to no way to guess control (having to study the tool at every use, or mark it so that it can be identified by feel, is ridiculous, IMHO). It would be different if function were somehow improved enough to justify, but I've never seen the situation where that was true [for this specific type of tool].

It seems that source manufacture country (US, Germany, Spain, Turkey and China is just a photocopy of the others) is not consistent. Does the reason lie in some vintage engineering practice or standard from a bygone era ?

At this point and time I don't think you are going to get a look at the design folder for the adjustable wrench, so we will never know if it was intended or not.

What I do know that in my extensive use of them I have found them to be a knuckle busting, ill fitting sorry excuse of a tool that ought to be relegated to the drawer of your toolbox reserved for either last ditch efforts or the occasional time when you are too lazy to look for the right tool.

Has to do with your thumbs ability to give higher (due to size) force than pointer so right-handers prefer the one in the right because they can give bigger torque to the worm with less effort so tighter

grip to the bolt. This is important sometimes for this tool because it's much less rigid than an equivalent standard spanner and also it doesn't stay new for ever which makes things worse. But if I was left handed I would prefer the other. Try it

usually we notice minor changes in design and appearance specially in standard tools. This might be cannibalised.