Can't find the screwdriver... HA!

HNB

http://quoteinvestigator.com/2010/05...erse-einstein/

He is credited to have said it. But what is said does not engage, only what's written does (who said that?).

ANYWAY...

"more efficient use of the motion" ???

Is a simple turning rotational motion of one hand less efficient than a (less simple) turning rotational motion of one hand, while holding the other part of the screwdriver with my second hand? I'd say no

Vanadium

Your forgetting the limited range of torsion of the wrist, which otherwise has to do an (time-) wasting backstroke -- likely up to 4 of them per rotation of the screw.

Don't get me wrong, I just saw the ad for the first time Friday morning, and while I thought it was nifty, I felt the rationale was weak: it is only said to fully set screws faster than rachet or manual drivers--which I can imagine, but how many people really need *that* and don't use (swiveling) electric screwdrivers? Even factories usually opt for a powered drive.

I might pick one up if I see it in the bargain bin, but I wouldn't count on *needing* it often.

This, paradoxically, may make it a good gift. The mechanically minded often appreciate mechanical niftiness, but also see the impracticality. Some say the best gift is something you'd enjoy but would never buy for yourself. A young man's dad may have more money, but this tool acknowledges dad's interests, and it is easily returned (Kobalt is the store brand of one of the big US hardware chains) to get something Dad wants more, when he gets bored of it.

Rhino169

After seeing the animation part (around (:28 seconds) of the video of the screwdriver in action, I am still left with the physics question as to how this gearing is accomplished. See video below:

http://www.youtube.com/watch?v=AtGR7nkless

Is this a new method of gearing unknown before now or has their already been this type of gearing in use in a different manner. It almost appears to be magic, even when I slow down the animation part. Thanks for any insite!

sketch

Isn't that what bolts and normal ratchet handles are for? At least you only need one hand....

Rhino169

I assume then that this is a patented device ...as far as you turn it both ways while holding the collar and it only spins in one direction? Still seems to be magic.

S_Happens

You CAN only use one hand with this device. If you do, then it works EXACTY like a normal ratcheting screwdriver. If you can/do use two hands and hold the collar, then the wasted stroke to ratchet it is instead ALSO used to turn the screw.

"Any sufficiently advanced technology is indistinguishable from magic." -A. C. Clarke

Of course it's going to be patented. Not being able to come up with an idea of how it works right off the top of your head shouldn't bother you. The video doesn't give you enough information to figure it out without any previous knowledge. Buy one and disassemble it if you like. (then post pics)

cmb

Aww.. shame. There goes the best option I have had this year for finding a Christmas present that defied the laws of physics!

Maybe I'll find one for next year...

cmb

Incidentally, mechanics have been doing this 'double drive' with a ratchet socket and extension bar for ages - what you do is grasp the extension bar in one fist and as you work the ratchet socket handle one way let the shaft slip, then while you are rotating the ratchet back against its 'click-click' ratchet you slide your grip as far around on the extension bar as you can, grip it, and then rotate that in the direction your doing the screw/bolt. This gives you double the 'periodic' angle of rotation through which you rotate the ratchet handle (twice as much as if you were to only grip the extension bar and hold it static). This screwdriver does exactly this.

I still prefer my Stanley Yankee ratcheting extending screwdriver. Much quicker, and definitely one handed!

It's a neat package all the same and looks like it would make a good Christmas present.

S_Happens

Now that you mention it, I do frequently do that. It only works on fasteners that are loose enough. I also pull the ratchet off and simply spin the extension with both hands.

cmb

I think this screwdriver will also only work on fasteners loose enough, because in the 'reverse' phase of the screw cycle it will be your grip on that thumb-wheel part that will be applying the torque, and I don't think you're going to be able to apply much with your fingertips into that.

S_Happens

It's a larger diameter than any extension that you're going to use, and textured vs polished/smooth.

But I agree, it will only turn fasteners that are loose enough that it is able to turn them.

sketch

^^^This

S_Happens

The part that's even better than you simply quoting the person in this thread that really didn't understand the device, is that it was already addressed by multiple other posts.

BTW, I did get one for Xmas.