Screwdriver length torque
Right, here's one for the experts.....my lil sis visited this evening, she had a temperature logger which needed the battery changing and although she had got four of the six screws out, the remaining two had mashed. They were not very high quality self tappers, obviously driven into the plastic case with an air tool on the production line in Romania.
Anyway, she sought the assistance of her big bro (me) to get the recalcitrant fasteners out somehow. So, after trying various combinations of Pozi #1, #2, a little screwdriver, then a big one, I finally picked out a #2 phillips driver with a 30cm long metal shaft that I bought off the local market for 3 quid about 20 years ago. Now this little puppy has always been very good for torque, and sure enough, it gave the extra purchase to crack the screws and get them out, despite the wrecked heads.
So, here's the thing....how does a long driver like this give the extra bite that a shorter one does not? This particular tool has always had that bit extra when it comes to a bit of clout, even though it's quite slender and certainly no Snap-On or Proto weapon. One would think that torque would be a direct function of radius from the centre of drive, but in this case it is the distance from the point in a straight line that makes all the difference.
Your thoughts.....?