On Sat, 24 Mar 2007 20:08:53 -0400, Gene Kearns
wrote:

I was doing some deck work and had bought some stainless deck screws
with the Robertson square drive.

The contractor who built my dock must have used several thousand.
They came in long strips, ready to load into a circular magazine,
almost like an ammo belt. They used a special driver with a long T
handle about waist high. Press down on the handle and it would grab
another screw from the magazine and drive it, all in one fell swoop.
One guy could drive about 10 screws a minute and they had very few
"break offs".

Perhaps your lumber is unusually dense?