# Advantage of longer screwdrivers, more leverage or...?



## ED65 (15 Aug 2016)

Stumbled across this by accident just a couple of hours ago, this is from the Shop Notes in the February 1926 issue of Popular Mechanics. 

As you can see it asserts that there is increased leverage screwing with a long handle as you can see, and the drawings seem to make sense:


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## Racers (15 Aug 2016)

More leverage due to a fatter handle, nothing to do with the angle that makes no difference to the force applied to the screw.

To test this grind a screwdriver tip to 45 deg then try turning a screw, should be the easiest thing in the world it if correct.

Pete


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## Peter Sefton (15 Aug 2016)

Not sure of the science behind it, but I would say using on long screwdriver on a bench would be to high for me to get any leverage or power on.

Cheers Peter


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## Cheshirechappie (15 Aug 2016)

There are several dodges to get 'more torque'. One is to apply an adjustable spanner to the flats of the screwdriver just above the screwhead, and turn the screwdriver with that. It's very easy to either shear off the screw shank, destroy the screw slot or destroy the screwdriver tip doing this. Don't ask how I know....

It's easier to grasp the handle of a longer screwdriver and turn it harder than one shorter and thus tighter up to the job, which may be the origin of the saying. As Pete suggested above, longer screwdrivers tend to have larger (fatter) handles, which will also help.

It's not true to say that two otherwise identical screwdrivers, one longer than the other, will inherently apply different torques. The torque comes from the operator, not the tool. The one that "applies more torque" will be the one that's easier to apply more twisting force to than the other, that's all.


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## timbo614 (15 Aug 2016)

With pozidrive screws and a good (right sized and not worn) bit and an extended and "locked out" large pump screwdriver (yankee) you can put enourmous torque onto a screw. Far, far more than any electric drill in screwing mode that I have ever used. It's why I stilll have two. You simply know it ain't ever coming loose! I don't think it's the size of the handle - that helps but a controlled "radius" that you can move the screwdriver in giving you better leverage (effectively an even larger hande). I don't think the same effect can be achieved with slotted screww.


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## NickN (15 Aug 2016)

For working on pianos and organs, the longer the better, just to be able to reach otherwise inaccessible screws.


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## Terry - Somerset (15 Aug 2016)

The leverage may simply be down to a bigger handle, but a longer blade should make it less likely that the screwdriver will slip out and spoil the screw head. Simply logic (I think) - ideally the axis of the screwdriver should always be in line with the screw (vertical??). In use it is difficult to maintain precise axial alignment - a longer screwdriver will minimise any angular error.

Terry


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## woodbrains (16 Aug 2016)

Cheshirechappie":13huocia said:


> There are several dodges to get 'more torque'. One is to apply an adjustable spanner to the flats of the screwdriver just above the screwhead, and turn the screwdriver with that. It's very easy to either shear off the screw shank, destroy the screw slot or destroy the screwdriver tip doing this. Don't ask how I know....
> 
> It's easier to grasp the handle of a longer screwdriver and turn it harder than one shorter and thus tighter up to the job, which may be the origin of the saying. As Pete suggested above, longer screwdrivers tend to have larger (fatter) handles, which will also help.
> 
> It's not true to say that two otherwise identical screwdrivers, one longer than the other, will inherently apply different torques. The torque comes from the operator, not the tool. The one that "applies more torque" will be the one that's easier to apply more twisting force to than the other, that's all.



Hello,

I don't agree with this. If torque came from the operator, then fitting an adjustable spanner to the screwdriver shank would make no difference. The operator supplies the force and torque is the distance that force is applied from the turning axis. Further from the axis, the greater the torque. Hence a bigger diameter handle will be able to apply more torque than a narrower one, and thus an adjustable spanner acting as a long lever will provide even more torque. A long screwdriver, slightly angled in the screw head, _for the brief time it takes to move a stubborn screw_ increases the distance between the axis and applied force, so makes longer screwdrivers better for removing stubborn screws. Clearly, if the screwdriver continues to turn with the angle not normal to the screw head, it will cam out, but it only needs a degree or two to start the screw moving, and (hopefully) the screwdriver operator quickly corrects the angle of the screwdriver fir a more axial one.

This is not the same as grinding a 45 degree angle on a screwdriver tip, as someone suggested above, as that would mean the screwdriver would have to be used as a lever, since it could not rotate in the manner we know screwdrivers to work, it would immediately cam out. Angling a screwdriver with a flat tip from the turning axis is not the same as angling the screwdrivers tip.

Mike.


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## Racers (16 Aug 2016)

The axis of a screwdriver is down the centre you can't change, it so tilting the screwdriver won't increase the force applied. 
A leaver needs a fulcrum and if the alleged fulcrum is out in space then you can't apply any force through it.
A screwdriver is a lever made by the difference between the width of the tip and handle.

Pete


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## John Brown (16 Aug 2016)

I can remember having this discussion about 35 years ago with a work colleague.
While it may well be the case that a longer screwdriver gives better results for whatever reason, it obviously isn't because it amplifies the torque in some fashion. If this were true, all you'd need to do would be to lengthen the back axle(or the prop-shaft) of your car to some ridiculous extreme, and you could set a new world land speed record.


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## woodbrains (16 Aug 2016)

Racers":3dzhmlxl said:


> The axis of a screwdriver is down the centre you can't change
> 
> Pete



Hello,

The axis of the turning force is down the centre, but the screwdriver blade is not necessarily in this axis, is it? In fact a screwdriver turned by hand is almost never along the normal axis, t wobbles around all over the place because humans cannot rotate their arms like a motor.

What I do know is, I have owned sets of screwdrivers over many years, that have stubby and medium and long length variants, with identical tip sizes, blade sections and handles. Can't remove a screw with a stubby, I almost always can with the long variant. There must be a reason, and this is as good a reason as any, though I'm sure the mechanics if it are much more complex in reality.

Mike.


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## Sawyer (16 Aug 2016)

I've always been a bit bemused by this one: longer screwdrivers certainly have their pros and cons depending on the specific situation, but how can the laws of physics possibly suggest that that longer = more torque? A fatter handle, yes, but only up to a certain point beyond which it gets harder to grip. What matters is that the humble cabinet handle is an ergonomic masterpiece and longer screwdrivers tend to have such a handle in the optimal size for the strongest grip.

Mike: the push factor is also important, so my guess is that longer screwdrivers allow more efficient upper arm leverage for pushing down on the screw.


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## Racers (16 Aug 2016)

woodbrains":qt1hrjde said:


> Racers":qt1hrjde said:
> 
> 
> > The axis of a screwdriver is down the centre you can't change
> ...



The angle of the screwdriver doesn't affect the axis of the force. You can't leaver against fresh air.

Pete


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## Eric The Viking (16 Aug 2016)

Unless you're doing constructional work, torque isn't of itself the important thing.

The tricky bit is getting the torque from whatever is driving it (hand/arm or motor) to the pointy part, where the thread is being made through the wood fibres. The interface between screw and driver is critical to this - if the driver can't engage properly, or deforms the screw head or shaft, that's wasted energy. I'm sure we've all put a fresh battery in a powered screwdriver ready to go, and the first screw we try... whoops! Chewed head and it's start again time!

I prefer my long-handled screwdrivers, so much so that, when I lost one for electrical work, I spent over a year looking for a good replacement. Then I found it again, after I'd bought two to replace it! 

They are better, especially with slotted screws, because they encourage you to work better. It's all down to angles: Some screw head designs will cope with a screwdriver used off-axis, such as Robertson, Torx and Pozidriv (to a slight extent). Others can be abused a bit but it does damage, such as Allen (hexagon) heads. 

Most screws - straight slotted and Phillips being the most important for us - are designed to work with the driver dead-on on the axis of the screw, and performance drops off rapidly when it isn't.

This is the main reason why you get on better with a big screwdriver - you can see the angle of attack clearly, and any wobble distance at the handle has far less effect at the screwhead than it might with a stubby screwdriver. You can also grip the handle better, as your hand isn't obstructed by the thing you're working on, or your other hand holding the screw, or whatever. And it is probably true, too, that you can position your elbow to get better driving torque - with a shorter driver you often haven't got room off he work's surface to get hand and arm into the ideal position.

As I get older, my grip gets worse. Years ago, I always used to carry a stubby Phililps screwdriver around with me in my briefcase(!), for getting into equipment (when there wasn't time to call maintenance, boss!). Now I hate using the things. 

Oddly, it's the same with power tools: I have a much better time using extended length driver bits in the screwdriver. I own a right-angled drill/driver too, and it's one of the most awkward things to use, mainly because it is so difficult to keep it straight on the screw head.

An aside: you're trying to get the power you produce through the head of the screw, to the pointy part, as efficiently as possible. I find diamond coated bits work really well for this, as they grip and don't cam out like ordinary bits do. It improves battery life, the bits last a lot longer, and they do a lot less damage to screwheads. They're so good, that I often use them hand-powered in a ratcheting handle, instead of with the powered driver.

So that's my three-and-fourpence-halfpenny...

E.


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## woodbrains (16 Aug 2016)

Hello,

I should do a drawing to illustrate, but I'm off out, so maybe later.

If you angle the screwdriver slightly, you are adding another axis of rotation described by the centre of the screwdriver handle about a point which has a radius equal to the distance the screwdriver is tilted from the screw axis. The longer the scewdriver, the longer this radius can be before the screwdriver tip cams out of the screw. This epicycle introduces a whole new torque system. The bigger the radius, of this epicycle, the greater the torque.

Mike.


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## Racers (16 Aug 2016)

A leaver needs a fulcrum, where is the fulcrum of an angled screwdriver? 

Pete


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## bugbear (16 Aug 2016)

Racers":dh7sxzsl said:


> A leaver needs a fulcrum, where is the fulcrum of an angled screwdriver?
> 
> Pete



The obvious proxy test here is to use a socket set breaker bar (*), which will engage the nut
at all angles from fully on-axis to 90 degrees off it.

https://www.amazon.co.uk/8-Inch-Drive-S ... B002GQ8K6W

Clearly, at 90 degrees, the intended mode of use of a breaker bar, massive
torque is generated, and equally clearly, when fully on-axis, you're
going to struggle to turn a stubborn nut.

The interesting question, for the purpose of this thread, is can
a breaker bar generate useful additional torque when only (say) 3 degrees off-axis?

Anyone got a nice big socket set and can try this?

BugBear

(*) I didn't know they were called that, but google is my friend


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## timbo614 (16 Aug 2016)

Eric has summed up what I was trying to say about the slightly off-axis advantage from a long screwdriver, we are only talking a tiny "radius" as I described it. Additionally with pumps the bit is not completely solid in the socket so the tiny angling needed may well occur at that point leaving the bit stil absolutely engaged in the screw head but the rest of the screwdriver body slightly angled. I may test this theory later. Also, as mentioned, I was referring to my days in construction (a long while back) when pump screwdrivers were in very common in use. If I need that much force with woodworking something else is wrong!
Added: There is definitely a knack to getting this final power twist right with a fully extended big yankee!


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## Jacob (16 Aug 2016)

A screwdriver is a hand tool and easily worked to the limit, where it either cams out or breaks the screw head. Any extra leverage would soon reach that point. Applying a spanner to the flat would soon wreck the driver or the screw.
The off-axis thing is a bit of a delusion - it helps if access is a problem but won't improve leverage - quite the opposite it'll take you nearer to the point of camming out.
The long screwdriver is simply more accurate and stable - as has been pointed out several times already, by several people!


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## woodpig (16 Aug 2016)

I don't know about slotted screws as I haven't used them for 40 years but I have two Stanley Pozidrive screwdrivers, one standard and one long length. It is obvious in use that you can apply more pressure with the longer screwdriver but it's not immediately obvious why. I suspect it's something to do with the position of the arm in relation to the body. I prefer Torx or better still, Square screws though, they're much easier to drive as they don't cam out like pozidrive.


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## Carl P (16 Aug 2016)

Cheshirechappie":39cfv1d6 said:


> It's very easy to either shear off the screw shank, destroy the screw slot or destroy the screwdriver tip doing this. Don't ask how I know....



Alas, I don't need to ask...


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## pedder (16 Aug 2016)

Just a quick thought.

Usually long tools are easier to keep straight. So maybe it is vice versa: 
The longer the screwdriver is, the lesser you will hold it off the angle 
and the more power you can transfer.

Cheers 
Pedder


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## happymadison1978 (16 Aug 2016)

Is there not a small degree of 'torsional flex' in the longer shaft? I know on some of the longer machine screwdrivers I've got I can feel a slight 'give' I'm not sure how that could translate other than a slight increase in stored potential energy as the shaft tries to return to equilibrium. Also not convinced you'd feel it on the monster turnscrew which fuelled this discussion!


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## Jelly (16 Aug 2016)

woodpig":1xl0yrbi said:


> I prefer Torx or better still, Square screws though, they're much easier to drive as they don't cam out like pozidrive.



I'm with you on that one, the world would be a much better place* if Robertson Screws were in common usage.

Posi-Drive is basically a step backwards from slotted and Phillips head... "You know what would help drive awkward screw? Making it easier for the driver to cam out of the screw head"


*This statement may be hyperbole... Only way to be sure: buy some Robertson Screws (available in solid brass for common furniture sizes) and see for yourself!


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## bugbear (16 Aug 2016)

Jelly":11nzhbbp said:


> Posi-Drive is basically a step backwards from slotted and Phillips head... "You know what would help drive awkward screw? Making it easier for the driver to cam out of the screw head"



Pozi drive is much less prone to cam out than Phillips; I recently replaced some Phillips machine screws with Pozi's so I could tighten them properly.

BugBear


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## Rorschach (16 Aug 2016)

bugbear":2fou2cxe said:


> Jelly":2fou2cxe said:
> 
> 
> > Posi-Drive is basically a step backwards from slotted and Phillips head... "You know what would help drive awkward screw? Making it easier for the driver to cam out of the screw head"
> ...



Yep, I rarely have problems with Pozi but have a lot more trouble with Phillips.


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## Jelly (16 Aug 2016)

bugbear":2a06clb3 said:


> Jelly":2a06clb3 said:
> 
> 
> > Posi-Drive is basically a step backwards from slotted and Phillips head... "You know what would help drive awkward screw? Making it easier for the driver to cam out of the screw head"
> ...



My mileage varies somewhat... Which would probably suggest I need to buy some better quality screws and/or drivers (or match poor quality, soft screws to poor quality soft drivers)...


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## woodpig (16 Aug 2016)

I bought a set of Robertson screwdrivers, a couple of sets of bits and half a dozen boxes of Robertson screws when I was on holiday in Canada about 15 years ago. I haven't bought any Pozidrive since. "Robbies" are very popular in the USA and Canada. Once you've tried them nothing else compares.


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## Downwindtracker2 (17 Aug 2016)

Robertson screws and screw drivers are very popular in Canada, not so much in the States. The design is older than Philips. 

Long handled screw drivers work like stethoscopes on machinery. Handy for locating that noisy bearing.


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## DTR (17 Aug 2016)

bugbear":14gcufd3 said:


> Pozi drive is much less prone to cam out than Phillips;



I'm led to believe this is by design? Before electric drivers had torque clutches, Philips were designed to cam-out before ruining the screw. Pozi were designed not to cam out as they should be driven with the benefit of a torque clutch.

Having said that, it's easy enough to destroy either one :?


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## bugbear (17 Aug 2016)

woodpig":29dm3mpl said:


> I bought a set of Robertson screwdrivers, a couple of sets of bits and half a dozen boxes of Robertson screws when I was on holiday in Canada about 15 years ago. I haven't bought any Pozidrive since. "Robbies" are very popular in the USA and Canada. Once you've tried them nothing else compares.



Future furniture restorers will curse your name, as they survey _your_ screws, and _their_ screwdrivers...

BugBear


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## Rorschach (17 Aug 2016)

DTR":3dr49k9o said:


> bugbear":3dr49k9o said:
> 
> 
> > Pozi drive is much less prone to cam out than Phillips;
> ...



If that was their design then it might work well when driving a new, well made screw into a properly piloted hole with a good driver bit. Fast forward a decade and it comes time to remove a poorly made screw put into a small or non-existent pilot hole and many years of paint, rust, swelling etc and what you have is a recipe for frustration and trouble. 

A couple of weeks back I did some DIY that involved removing screws that had been in about 15 years, some were pozi, some were phillips, the pozi were much easier to remove by far.


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## Phil Pascoe (17 Aug 2016)

woodpig":2t3mumdt said:


> I bought a set of Robertson screwdrivers, a couple of sets of bits and half a dozen boxes of Robertson screws when I was on holiday in Canada about 15 years ago. I haven't bought any Pozidrive since. "Robbies" are very popular in the USA and Canada. Once you've tried them nothing else compares.


My b.i.l. worked as a joiner in NZ up to about 10 years ago (a bit of time perspective) and he told me they never used anything else.


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## AndyT (17 Aug 2016)

BB, I think a future restorer would do what I did when I came to dismantle a Canadian made garden chair - lash out a whole pound at my nearest tool shop and buy a square drive screwdriving tip, to go in an electric or hand powered screwdriver!


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## woodpig (17 Aug 2016)

Rorschach":xyg5btrj said:


> If that was their design then it might work well when driving a new, well made screw into a properly piloted hole with a good driver bit. Fast forward a decade and it comes time to remove a poorly made screw put into a small or non-existent pilot hole and many years of paint, rust, swelling etc and what you have is a recipe for frustration and trouble.
> 
> A couple of weeks back I did some DIY that involved removing screws that had been in about 15 years, some were pozi, some were phillips, the pozi were much easier to remove by far.



I had to take out the Philips screws holding our old shower unit together with mole grips.  I only just managed it, the hammer and chisel were primed ...


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## Rorschach (17 Aug 2016)

woodpig":187trok9 said:


> Rorschach":187trok9 said:
> 
> 
> > If that was their design then it might work well when driving a new, well made screw into a properly piloted hole with a good driver bit. Fast forward a decade and it comes time to remove a poorly made screw put into a small or non-existent pilot hole and many years of paint, rust, swelling etc and what you have is a recipe for frustration and trouble.
> ...



Funnily enough one of the jobs I did was removing parts of a shower. The impact driver was needed to remove the screws, both screws and drivers were knackered at the end but I did manage to get them out without damage to the tiles or shower. Replacement screws were pozi.


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## Racers (17 Aug 2016)

woodpig":5k6uz9iu said:


> I had to take out the Philips screws holding our old shower unit together with mole grips.  I only just managed it, the hammer and chisel were primed ...



Didn't you have a Philips screwdriver?

:wink:  

Pete


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## bugbear (17 Aug 2016)

Racers":22gjfc8z said:


> woodpig":22gjfc8z said:
> 
> 
> > I had to take out the Philips screws holding our old shower unit together with mole grips.  I only just managed it, the hammer and chisel were primed ...
> ...



Phillip wanted it back.

BugBear


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## monkeybiter (17 Aug 2016)

I keep flat screwdrivers for three reasons;
When Posi or Phillips screws are a pain to remove, gentle tapping a flat driver while rocking back and forth first in one 'slot' of the screw then 90' around in the other will usually clear paint/deepen the pattern enough to remove and dispose of.
Long flat screwdrivers can be made into special profile turning tools with minimal work [shock horror!] and can cost as little as £1.
Old stuff that needs repairing where the screws are bloody awful slotted things.

I find the easiest way to deliver max manual torque [for me anyway] and avoid chewing the head is to push against the end of the screwdriver with one hand, [down it's axis] while gripping the handle of the driver at right angles 'from the side' with the other, separating the 'don't-cam-out' force from the 'turn-you-pipper' force.


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## Limey Lurker (17 Aug 2016)

There are some posts in this thread that have gone missing.


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## monkeybiter (17 Aug 2016)

Limey Lurker":2oicahrh said:


> There are some posts in this thread that have gone missing.



I immediately looked to see if Jacob's post was still there, but it is! And very sensible and non-controversial too.

What's missing? The page count is the same as just before I posted, surely can't be much? Was it significant?


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## custard (18 Aug 2016)

I use flat screwdrivers because I use flat screws! 

There are some modern furniture designs where a Torx head or something similar looks appropriate, but in most fine furniture anything other than a slotted head brass screw just looks wrong.


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## John Brown (18 Aug 2016)

Limey Lurker":2f1rgl7e said:


> There are some posts in this thread that have gone missing.


It's probably all part of an anti-long-screwdriver conspiracy.
Alternatively, you could be forgetting that this thread was split off from another one.


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## bugbear (18 Aug 2016)

monkeybiter":33k09ec5 said:


> I find the easiest way to deliver max manual torque [for me anyway] and avoid chewing the head is to push against the end of the screwdriver with one hand, [down it's axis] while gripping the handle of the driver at right angles 'from the side' with the other, separating the 'don't-cam-out' force from the 'turn-you-pipper' force.



If only there were a tool that embodied this _excellent_ idea...

bad-but-good-brace-t99495.html

BugBear


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## AndyT (18 Aug 2016)

bugbear":2jlb0jwt said:


> monkeybiter":2jlb0jwt said:
> 
> 
> > I find the easiest way to deliver max manual torque [for me anyway] and avoid chewing the head is to push against the end of the screwdriver with one hand, [down it's axis] while gripping the handle of the driver at right angles 'from the side' with the other, separating the 'don't-cam-out' force from the 'turn-you-pipper' force.
> ...



Indeed!

Or even one of these - I've still not seen another, over seven years later.


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## monkeybiter (18 Aug 2016)

bugbear":3f544tjs said:


> If only there were a tool that embodied this _excellent_ idea...
> 
> bad-but-good-brace-t99495.html
> 
> BugBear



You'd definitely be able to deliver more torque, but I think you'd also have more chance of pushing out of alignment.... wel, I would, but in retrospect that's probably a case of acquiring a knack. 
Hmmm may have to start and look out for one as a 'stuck screw wagger'.

AndyT's tool looks like a complicated toffee hammer.

Re. screw head types, I was trying to be mischievous/provocative but I do think the apparent consensus on the aesthetic superiority of slotted screws strange, in a jewellery box for instance I think I would prefer the appearance of an Allen head or even Pozi/Phillips. I don't think I'd like the look of a square drive.


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## bugbear (18 Aug 2016)

monkeybiter":7y1zwg8l said:


> bugbear":7y1zwg8l said:
> 
> 
> > If only there were a tool that embodied this _excellent_ idea...
> ...



As you said, one hand is entirely dedicated to pushing into the screw (and maintaining alignment...) the other provides nothin' but torque.

In practise, with a stiff screw, I find it's normally the pushing (anti cam out) force which is the highest; the leverage/torque provided by the sweep of the brace is _enormous_ compared to the screwdriver, which is a why I use a small brace.

BugBear


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## Cheshirechappie (18 Aug 2016)

It's just occurred to me that cranked screwdrivers are available. I think they're mainly intended as a way to turn screws in hard-to-reach places, but their nature does allow more turning force on the screw. From experience, they're actually quite hard to use; keeping the business end in proper alignment with the screwhead is difficult.

I'm in whole-hearted agreement with Bugbear on the use of screwdriver bits in braces, though. For removing larger, well-stuck screws, there's nothing better, especially as the brace allows you to keep the bit in good alignment with the screw, and keep a good axial force on to keep the bit engaged in the screwhead. I've found that with bigger screws - Number 12s and above - you can use a 10" sweep brace safely enough; with smaller screws some discretion with turning force is wise!


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## DoctorWibble (21 Aug 2016)

Going back to the long screwdrivers I think the key is the spring allowed by the longer shaft. Spring allows you to build up the pressure without breaking your grip on the handle or losing your alignment with the slot. Total torque or power is unchanged (of course) but it is more controllable and so is directed into turning the screw rather than burring the head or heating your hand and the handle with friction. 
The length as has already been suggested also minimises tipping at the tip but this is possibly a minor benefit. I have a set of bahco jewellers screwdrivers made out of particularly spinrgy alloy. They're brilliantly controllable. You just wind them uip a bit and the screw loosens as if by magic with no camming or sudden release to kick the screwdriver out the head.
I wonder whether the waisting on these long screwdrivers is done to modify this effect in some useful way?


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## woodpig (21 Aug 2016)

monkeybiter":17mfey4u said:


> I don't think I'd like the look of a square drive.



It's a personal thing but I think they look far nicer than Pozidrive.


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## Downwindtracker2 (21 Aug 2016)

If you're a Canuck, everything else is an abomination , truly either the work of the devil or yanks.


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## Jacob (21 Aug 2016)

DoctorWibble":qrtj1m05 said:


> Going back to the long screwdrivers I think the key is the spring allowed by the longer shaft. Spring allows you to build up the pressure without breaking your grip on the handle or losing your alignment with the slot. Total torque or power is unchanged (of course) but it is more controllable and so is directed into turning the screw rather than burring the head or heating your hand and the handle with friction.
> The length as has already been suggested also minimises tipping at the tip but this is possibly a minor benefit. I have a set of bahco jewellers screwdrivers made out of particularly spinrgy alloy. They're brilliantly controllable. You just wind them uip a bit and the screw loosens as if by magic with no camming or sudden release to kick the screwdriver out the head.
> I wonder whether the waisting on these long screwdrivers is done to modify this effect in some useful way?


Interesting. OK I'd go with that idea. Presumably a flat bar be more twisty than a round one (a.o.t.b.e.)?


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## monkeybiter (22 Aug 2016)

woodpig":2jg5px0m said:


> monkeybiter":2jg5px0m said:
> 
> 
> > I don't think I'd like the look of a square drive.
> ...



OK, That's a good example, I can feel my mind opening.


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## happymadison1978 (22 Aug 2016)

DoctorWibble":1dowk4sf said:


> Going back to the long screwdrivers I think the key is the spring allowed by the longer shaft. Spring allows you to build up the pressure without breaking your grip on the handle or losing your alignment with the slot. Total torque or power is unchanged (of course) but it is more controllable and so is directed into turning the screw rather than burring the head or heating your hand and the handle with friction.
> The length as has already been suggested also minimises tipping at the tip but this is possibly a minor benefit. I have a set of bahco jewellers screwdrivers made out of particularly spinrgy alloy. They're brilliantly controllable. You just wind them uip a bit and the screw loosens as if by magic with no camming or sudden release to kick the screwdriver out the head.
> I wonder whether the waisting on these long screwdrivers is done to modify this effect in some useful way?




Thanks DoctorWibble, you put it a heck of a lot better than I did. You can indeed feel a degree of 'pre-load' (potential energy in my nerdspeak) and they definitely feel more progressive and controllable.

Cheers,

Stephen


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## DoctorWibble (23 Aug 2016)

Turns out the small springy screwdrivers I mentioned were actually made by Wiha not Bahco. The Pico line. Looking at them a bit more closely its possible the spring or whip might come from a slightly elastic handle material rather than the alloy chosen for the blade. 
As makers of old only had the option of wood for the handle then they'd need to find all the properties they need from the blade. Perhaps this rather than reach is the reason for the variety of long lengths. 
Maybe too some were intended to allow two man operation? One "steering" and the other adding some turning force with a pair of mole grips or pliers. If so the length would've made more room for them to work. Mind you if that was the case the makers might've helped by providing a hole for a tommy bar or something so perhaps not.


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## Green (28 Aug 2016)

I always thought that the longer length allowed the shaft to twist and act like a torque converter.


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