Driving screws ...

Interesting... Maybe the longer screwdriver lets you apply more of your arm strength by moving your hand farther away from the wall?

With the shorter one, were you in a slightly more awkward position and trying to use just your wrist to turn it?

That's a good thought. Maybe. If anyone doesn't believe this, just try it ...

Arfa

Hi...

Don't have to try it, been there, done it. Didn't ever get the tee shirt though :)

I'm old and stroke damaged, so can't explain my theory nearly as eloquently as I'd like to, but my idea goes something like this...

When you turn the handle against the resistance of the screw, you're to a small degree "winding up" the shaft. Naturally the longer the shaft the more you're able to wind it up.

When the screw resists, it's not linear, but rather full of intermittent and random heavy resistance spots and easy spots.

When the long shaft encounters one of these don't wanna spots, the shaft winds up until it finally overcomes the resistance.

Someone please explain it better for me :)

Take care.

Ken

I'm following that ok Ken, and it's another good thought. There used to be a little car over here called a Morris Minor, and it employed just what you're describing, for its front suspension. "Torsion bar suspension" it was called. A bar a couple of feet long ran alongside the chassis members on each side. One end was fixed ( but adjustable ) and the other end was connected to the lower suspension arm. The bar twisted as the suspension arm moved, and provided the springiness. I think that is what you are thinking of as being the mechanism at play here.

I might try sticking the business end of the driver in a vise, and seeing if I can indeed introduce some twist into the shaft.

Arfa

Arfa

Yes indeed, but as I said in the original post, the handles of the two drivers were much alike, as was the shaft diameter and tip dimension. The long driver is just that really. A perfectly normal 'average' sized tool, but with a very long shaft. I originally got it many years ago when I had to work on some graphics terminals, where the metal cabinet was secured to the front bezel, by two screws located right in the top corners of the case. The screws were spring loaded, so had to be driven *very* straight to get them to locate without cross-threading. The only way to do this was with a screwdriver 18" long, which was enough for the handle to be outside the back of the case.

Arfa

Just as an aside I was watching a CSI the other night where they were dismantling something in the lab using a dumpy screwdriver. Which absolutely no one would use unless forced to by space. The answer was, I reckon, it made a better framed close up in widescreen...

My theory goes like this: Short shaft, you are mostly using the wrist to turn the screw driver. Wrist muscles tire easily.

Long shaft, you can use your arm and shoulder (which are capable of greater strength) to rotate the screwdriver via a "locked" wrist (and if not locked, the twisting motion is shared by the forearm and wrist). Much easier on the wrist alone, which isn't known for it's strength. Having a longer shaft means it's easier to use your weight to lean on the screwdriver, keeping it in the screws' slot. Much harder to do with a short one.

So it's not the screwdriver, per se, but which of the body's muscles you can put into play that make one screwdriver "easier" than another.

That's an interesting one Dave, and it kinda backs up what I'm saying. Even though you would expect to get a good 'torque multiplier' effect from the fat handle that those dumpies usually have, in fact it is actually very hard to undo a tight screw, or get a decent tighten on one either. If I'm forced by space to use one of them, I often finish up with a pair of Mole grips locked on the shaft to get enough purchase.

Arfa

There were a whole lot of cars over here that used torsion bar suspension--the Chrysler Corp. By the way one of my neighbors has a restored Morris Minor, never drives it though. My 64 Chrysler used the torsion bar idea for keeping the trunk up. Marshel

Hi Dave This is the sort of theory that I have been coming around to as well, as I couldn't see any science that would explain it in terms of the physics of the screwdriver itself. I mean, you wouldn't expect a rear wheel drive car with a long prop shaft, to develop more torque at the diff, than one with a short prop shaft, given a similar engine and gearbox, would you ?

I actually tried to visualize which muscles I was using, and whether it was anything to do with a locked wrist, at the time, but it was hard to say, which is why I was interested to hear the opinions of others who must have come across the phenomenum. I am sure that you must be right, but it is still difficult to see how such a subtle shift in muscle usage, produces such a huge difference in the amount of effort that can be applied to the tool.

I suppose that it's a bit like the difference between a drummer, and a 'good' drummer. You can see some thrashing away at their drums, and only producing an average sound, whilst others seem to be putting hardly any effort in at all, and producing a really 'big' sound. Down to the technique of using the right muscle groups to put the force into the drumsticks, I guess.

Arfa

If the long-shaft driver is perfectly in line with the screw, there is no advantage. However, with a long-shaft driver, it's pretty easy to let it lean to the side a bit, and when you do that, the amount "off to one side" it is, gives you additional leverage -- like a short handle on a socket wrench.

Isaac

Even

hard

forced

a call on sci-med ? Who would ever use dumpy screwdrivers unles restricted access. My dumpy ones have parallel flats that i've ground into the shaft to take adjustable spanner.

-- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on

That's an interesting one. I'm gonna have to think on that a bit ...

Arfa

It also may be useful to note that the longer shaft gives one more options on how to hold the tool. Likely one holds the screwdriver in a different fashion when the screw is stubborn (or simply tight). I know that I vary my grip depending on the amount of force necessary to remove a given fastener. A stubby can only be held in a limited number of ways.

jak

The longer screwdriver has a sharper more newlike tip that stays in the screw better . The long drivers dont get used near as much as the normal familiar size which will have a sligtly worn tip causing you to fight it harder to keep the driver in the screw .