-MIKE- wrote:
On 8/1/14, 5:20 PM, Bill wrote:
-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?

For the same reason you lift your feet when you walk.


I don't get that either. A screw is a helical ramp, more or less.
You turn it to go in and come out. The farther the screw is in, the
more friction/resistance there is in both directions. Most often, I
find it necessary to push on a screw when removing it, at least until
it's a good deal out.

What am I missing?



Well, I should clarify my remark, since there appears to be at least 2
factors:
1. The friction (between the bottom of the screw head, and the
workpiece) that I alluded to.
2. The fact that you are pushing "down" when you wish for the screw to
come "up", that has been mentioned.