Every craftsman knows this to be true, but the question is, why is it so ?
I could see if the screwdriver were being used as a lever, then the extra length would give a mechanical advantage, but when the screw slot, the blade and the wrist are all in the same line, with the same central axis, then you would think that a short stubby driver would be just as efficient as a long bladed driver.
But it isn’t …
At a guess it’s because the longer ones usually have bigger handles that you can grip better and get your whole hand around. Shorter ones, even if they have big handles probably don’t leave enough space for your hand and arm to do its twisty-wristy movy-woovy stuff (this is how carpenters talk, right?)
Because it contains more vodka. Duh.
(HS has it right, IMHO.)
Not so, I have to say, although that is a natural assumption.
A 12 inch long screwdriver has ample space for the twisty-wristy movy-woovy stuff (and yes this is exactly how carpenters speak) but a 2 foot long driver with exactly the same handle is much more efficient
Cite, explanation or justification?
It all has to do with the mechanics of how you handle the screwdriver. With a stubby screwdriver, there is usually only enough room to hold it with one hand (the driving hand), which has to be held from the end. This means that in addition to the applied torque and axial force (to keep the head fo the driver in the slot), lateral force is applied by the same hand to ensure that the screwdriver is in line with the axis of the fastener. With a longer driver, the non-driving hand is typically used to ensure alignment. This may not seem like a lot of force until you look at the lateral torque that has to be applied to keep a screwdriver in line. The axial force is applied on the gripping area of the handle rather than at the end, which gives more traction for torque (the entire finger length and upper palm) than holding it from the end with just the fingers, as a stub screwdriver is often held. It is also the case that it is easier to visually assure alignment with a longer screwdriver (longer length allows the user to see that the angle is off-normal) and in tight spaces the longer shaft may allow a better hand position (see the discussion of applied torque above).
Stranger
Thirty years as a carpenter, that’s the cite. You don’t believe me, go ask any carpenter.
The **explanation ** of the phenomenon is what I am trying to find out here, from people smarter than I …
Um, thirty years of anecdotal evidence isn’t proof that the longer driver *is *more efficient, especially not when you’re insisting that the difference between one foot and two is significant. Between a stubby and anything longer, perhaps. But I really think you need to establish the effect before we get too deep into any purported cause.
I have about forty years of tool-handling experience* myself, more as a mechanic than a carpenter - frankly, I’ve used a screw-gun for the last twenty years in carpentry and construction; there’s efficiency for ya - and have a pretty good sense of what works, what doesn’t and why. Show any evidence that a two-foot screwdriver is “more efficient to use” than a one-foot one, and we can move on.
*Shaddup, smartass.
Do you have a published cite? It’s necessary because the claim, at least on its face, is implausible. That, however, does not mean false, and that’s why me and others are looking for cites.
Stranger On A Train has it.
if you use a longer driver one handed you may find it more difficult, it’s harder to keep on axis.
with lots of practice you can develop techniques using shorter drivers one handed and stay on axis.
I have a long, thin, Philips screwdriver I call my “second favorite tool.” 
It is about the only tool I need to fix or install computers. I can’t say it’s more efficient than a shorter one, but it has two characteristics I like:[ul][]It can reach deep in cabinets or in narrow places[]It can “twirl” to rapidly insert or remove a screw, something a shorter driver with less weight can’t do as well.[/ul] And I magnetized the tip, so it can insert or remove screws in hard-to-reach places, too.
No published cites, but as I say, ask any carpenter who has ever had to remove rusted screws from the hinges on an old door. He will vouch for the fact that using a 2 foot screwdriver in that situation is a hell of a lot more efficient than using a 12 inch driver.
Now, I am **not **suggesting that using a 3 or four foot screwdriver would be even more efficient, I think 2 foot is about the maximum efficiency.
The more I think about it (and I have never given it a great deal of thought before), the more I believe that it is all to do with being able to get your shoulder directly above the wrist, which enables you to exert maximum torque …
It depends upon the size of the screw.
Smaller than a certain size means you will have difficulty keeping it online, but once you start getting to the larger sizes of screw than it helps enormously if you can get your shoulder behind the force you need, and you’ll find on a shirt screwy that you just can’t do that. Once you get longer screwies than that though, you will find it is harder to keep straight, and also you may find some twisting of the screwie itself.
For those of us non-wood butcher types, it is always much better to have a screwy that is the exact size of the head you are screwing - the less play in the head the better
The difference between a stubby screwdriver and a standard one is going to be about handling (as Stranger On A Train said).
The difference between standard and two-feet-long - if there is any difference - is going to be what? - either torsional springiness in the shaft, or just the fact that if you drive it with one hand and steady the tip/screw with the other, you’re using your arm drawn right back (although that doesn’t immediately seem very much more comfortable or efficient to me).
This discussion is moot until you decide what you are defining *efficient *to mean.
Nope, a longer screwdriver provides the same torque, as long as the shaft and handles are identical, of course. They may provide you with a better grip or get it closer to your body where your muscles can get more leverage, but otherwise, like I tell all my dates, length doesn’t matter.
You’ve pretty well nailed it …(or maybe screwed it)
The increased efficiency of the longer (2 foot) length of driver is apparent when you are trying to remove really recalcitrant large gauge screws (such as in old door hinges) and the increased efficiency is undoubtedly because you are able to use your shoulder and elbow to exert greater torque than you could with a shorter driver.
Worth pointing out btw that in the “old door” situation, with slotted screws as opposed to Phillips or Robertson screws, the impact driver and cordless screwdriver are useless …you need an old fashioned screwdriver (with the correct size of tip, natch … )
For normal use, with properly drilled pilot holes , the difference is negligible.
I’m still waiting for a validation of the difference between a one-foot driver and a two-foot driver. I just tried and can get exactly the same position and leverage, relative to a flat surface, with both. The footlong was much easier to handle as well.
Is it that the extra foot is needed to clear beer-gut distance?
The difference comes from the fact that it is easier to properly align a longer tool.
I think the screwdrivers that have square shanks are better than the round shank ones. Makes it easy to add a wrench for some awesome torque, regardless of screwdriver length.