"Chris Friesen" wrote in message
...
Roger Shoaf wrote:
"Pat Barber" wrote
For the life of me, I can't imagine the "why" on this
design.


...and the Robertson screw square head tends to snap off bits.

Really? I've never snapped off a Robertson bit or screw head, and I've
driven screws that took both hands to resist the torque of the power
driver.

I can only imagine that you were either screwing into something really
hard with an impact driver (in which case it should be pre-drilled), or
else the bit had a manufacturing flaw.

Actually proper use of an impact drive is actually easier on the head of a
screw. Trying to drive a screw farther than it should be driven with an
impact driver can cause a break as with any type driver.
3 weeks ago I built an entire deck cover using the less than ideal common
Deck Screws and used an impact driver to drive the majority of that 5 lb.
box of those 3" screws I broke no screws but did break 2 bit drivers
because of an improper union of the screw and bit. This happened on the
same screw.
I have broken several square head screws with a 9.6 volt drill usually
because the screw was too small for the application or the wood was too hard
for the size screw.