On 1/18/2012 6:27 AM, Leon wrote:
On 1/17/2012 9:06 PM, wrote:
On Tue, 17 Jan 2012 20:46:16 -0500, wrote:

On Tue, 17 Jan 2012 17:04:54 -0500, wrote:

Canadians have known that for over 50 years - "robertson" screws are
VERY common up here. Used to be they were all Canadian made quality
stuff, now much of it is the same cheap Chinese CRAP you guys get
south of the lakes.

Naturally we've know that because Robertson was Canadian. One of the
advantages of Robertson screws is that the square drive gives extra
holding power which permits more torque on the screws. And if you're
adding more torque, then you don't want a cheap version of the screw
that might snap off. ~ Nothing more irritating. That is the biggest
reason to buy better quality when it comes to square drive screws.
The BEAUTY of a robertson screw is you can stick the screw on the
driver - point it vertually ANYWHERE and not worry about loosing the
screw when you try to start it - even into sheet metal or wood with no
pilot hole drilled. Makes it's own awl.

The draw back to the Robertson screw is that you can stick the screw on
the driver and drive the screw into the wood and play hell pulling the
drill and bit off of the screw. Yes this happens more often than I wish
and normally when I am reaching into the back of a cabinet mounting
drawer slides and or supports.



THE ANSWER

Taken from


http://www.instructables.com/id/When.../Square-Drive/

A "fresh" US square drive driver with a "real" Robertson screw head
sticks so tightly that it can take a significant yank to get them
disengaged.

I suspect that because many SD screws are imported from the Asian areas
of the globe that Robertson stylescrews probably are copied and mixed
with Square Drive screws.

Soooo apparently I am wrong about the Robertson being at fault however
the Robertson is part of the resulting problem when the SD drive is used
with a Robertson screw.