On Sat, 02 Aug 2014 16:22:06 -0400, wrote:

On Sat, 02 Aug 2014 12:18:42 -0400, wrote:

On Sat, 02 Aug 2014 00:55:33 -0400, wrote:

On Fri, 01 Aug 2014 22:33:16 -0400, wrote:

On Fri, 01 Aug 2014 21:15:10 -0400, Ed Pawlowski wrote:

On 8/1/2014 8:25 PM, Grant Edwards wrote:
On 2014-08-01, -MIKE- wrote:
On 8/1/14, 3:45 PM, whit3rd wrote:
But when you want to REMOVE a screw, you don't
want to apply a push (this hurts you because it increases friction).


I don't get this. Why not push when removing?

Because the objective is to _raise_ the screw. Pushing down on it
makes that harder to do and thus requires more torque to raise it. To
get more torque without cam-out you have to push harder, which then
requires more torque to raise the screw, which requires you to push
harder...


Theory aside, when the head is buggered, pushing gets it out, not
pushing makes the bit slip. One law of physics out does the other.

That doesn't mean pushing down is making it easier (than it would be
were a different head chosen up-front).


Anyone with a torque screw driver want to do a test? Drive several
identical screws into severel peices of different woods then read the
torque required to remove them with no downward force, and with , say,
5, 10, and 15 lbs of force pressing on the screw and tabulate the
results? In both hard wood and soft wood - and using both steel and
brass screws.
I'd be willing to bet the difference in torque required would be
within the limits of the torque required to lift the downward force
treating the screw as a simple inclined plane. (in other words,
insignificant).

Your test is silly beyond belief. Now try it with screws that have
weathered for a decade.
Not nearly as "beyond belief" as thinking the pressure you apply to
the head of a screw to keep the driver engaged is going to increase
the torque required to remove screws that have weathered a decade due
to increased friction in the threads!!!!

Sorry, but physics being what it is, friction matters.

You really do not have a CLUE.

Come on, throw some more bull**** when you're called on it.