It’s down to the larger handle on your long screwdriver, you can apply more torque and grip with the larger handle.

MichaelR

I based my reply to the posters question by my experience when serving my time in the 1950s if we got stubborn screws we used what they call a London pattern screwdriver it had a handle with flats on both faces you could really get a good grip and torque, they generally shifted the stubborn screw.

MichaelR

I do remember reading this fact in an old motorcycle book (1930s), but it didn’t explain the reason(s).

Rob

I’ve always favoured the slightly-tilted-greater-leverage explanation.

But could the handle diameter make the difference? I’ve just tried a not very scientifically rigorous experiment using the screwdriver handle and extension bars from my 1/4″ drive socket and screwdriver bits set.

I drove a couple of screws into a piece of MDF, one with just the handle, one with the extensions, as tight as I could turn:

The screw on the left was driven with just the handle, the one on the right with the extensions. The right hand one has sunk deep into the MDF whilst the other has barely sunk to the depth of the countersink; no pilot holes were drilled.

I think that gives a reasonable demonstration that the handle is not the deciding factor (though it certainly makes a difference).

Ideally, to investigate further one would use some more accurate torque measuring device – one of those moving pointer torque wrenches would be good.

Can’t do that I’m afraid Roy. I got rid of all my slotted screws when I retired (in fact I had to poke around to find screws with ordinary threads – I mostly have the fancy fluted ones which drive too easily to make good “test instruments”).

An undoing test would certainly need a torque wrench-type of measurement methinks.

I usually used the Yankee for undoing stubborn screws – 430mm overall length (unextended, not counting the bit), but the handle isn’t that much bigger than shorter screwdrivers – about 40mm diameter at its widest, as against 35mm for a 220mm long Wiha electrician’s screwdriver.

Older books use ‘turnscrew’ (which the spell checker has just underlined), I wonder if ‘screwdriver’ was originally an Americanism – it sort of sounds like it could have been.

As Roger implies above, I think your posture changes with the longer driver. My favourite for applying torque is a driver bit in a brace. One of our Shedders as his dementia took hold like to hammer screws in and contended screwdrivers were only for removing them.

I agree that a longer driver makes it easier but I don’t buy the “torque build up” argument. The torque at the screw head equals the torque applied at the handle statically. I think it’s to do with being far enough from the job to get a good stance and get your weight on the axis to stop the driver keying out.

I just find long shafted screwdrivers easy to use.

JA

Tbh, I agree with others and can’t think of any reason within the laws of physics how a longer length of screwdriver shank might somehow be capable of increasing the torque to make removal easier. A different body stance, larger handle diameter or even shape to increase grip I could understand and agree with. But the screwdriver shank length isn’t magically increasing the torque.

How much torque a screw head might withstand? There’s also the large difference between the cheap, cold headed, usually softer and mass produced slotted screws. And those with machined slots present on much of what we might own. Metrology equipment for example. Many machine tool manufacturer’s in the past used the same type, South Bend for another example. Sadly, and what most manufacturer’s seem to pass off today as an acceptable screwdriver tip shape someone might mistakenly use while removing those screws with machined slots couldn’t be any worse. I did the same at one time and buggered up my own share of screw heads until I read why that happens.Those common tapered tip screwdrivers we all own apply the torque right at the top of the screw slot which is the absolute weakest area of the head. Increasing the torque with those for any stubborn or tight screws almost guarantees visible screw head damage, part of the head breaking off, even the tip camming out of the slot and damaging the screw head even more, Or worse, sometimes damaging the surrounding area of the screw location. A fine gun stock as a common example.

For some uses, the inherent design flaws of those tapered tips may not matter.  An online search for the type of slotted screwdriver tip design sold to and used by gunsmiths, instrument technicians, watch and clock makers and many others  would show that none of them use those taper tip screwdrivers. And for very good reasons. The proper tips would be parallel ground, chosen to properly fit the particular screws full slot length, depth, and with almost zero clearance to fully fit inside the slot width. Depending on what else is available, you can then apply more than enough torque that the screw will loosen without any damage, or the head shears off. My tapered tip screwdrivers gather a lot more dust on them than they once did, and it would now be a rare screw that can’t be removed without damage.

One of my best screwdrivers has a wooden handle.  The steel shaft is square in section and has a  hex nut machined at the base of the handle.  Can use a spanner for addition torque when doing up or releasing screws.  The shaft passes fully through the handle and can be hit with a hammer without damaging the wooden handle.  Now its an impact driver.  Any tight woodscrew gets a tap on  the end of the driver with a hammer whilst twisting the handle.  The shock helps to free the screw.  Additionally the tip is hollow ground and so pulls itself into the screw slot.  If i remember correctly this was one of my grandfathers and has to be at least 80 years old.

I try and hollow grind all my flat blade screwdriver tips.

Colin

Would those be branded SCRURITE ?

I picked one up recently, at a very good price, with similar repair work.

… a mighty beast of a screwdriver !

MichaelG.