On 7/5/2011 12:42 PM, Leon wrote:
On 7/5/2011 10:12 AM, Jack Stein wrote:
On 7/5/2011 10:28 AM, Morgans wrote:
Torque down a drywall screw on a couple pieces of hardwood, and you will
hear the snap of the shank breaking before the head gets driven flush,
every time. ;-)
Torque any screw into hard wood, trying to drive the head flush, and you
are looking for trouble. Hard wood needs a pilot hole and a countersink.
Even in soft wood, a countersink is best or you can crush the wood
before you get the head flush.
Actually I can use a regular #8 flat head square drive screw with out a
pilot hole in 3/4" red oak. Using an impact driver, when the head begins
to bury inside the wood the wood will split. That was just to test the
strength of the impact driver.
And that is why I switched to square drive screws 20+ years ago.
OK guys, I just exited my shop after testing this out.
Using a 2" coarse thread #8 head dry wall screw, a Mcfeely's Robertson
2" #8 and a Home Depot 2" #8 outdoor screw and a scrap piece of 1 1/2
white oak (harder than red oak). I drove all of them right down past
the countersink level with my impact driver. I did this 5 times with
the drywall screw to see if a hot screw would snap as Mike suggested,
and it was hot as hell, but didn't snap.
No lubrication used, no pilot holes, no broken heads, no broken shanks
and no cam out with *any* of them. I even drove a couple of them all
the way through until the white oak split. So much for Morgans
statement that the drywall screw will snap every time. Wrongo!
The Drywall screw actually was the easiest to get started I think
because it has the sharpest point, and to my surprise, the McFeely
Robertson was the hardest to get started and, here's the surprise, was
harder to keep the drill bit in when starting the screw. That may have
simply been because the point wasn't sharp as the drywall screw.
I don't think I ever tried driving a screw into a 1 1/2" piece of white,
or red oak w/o drilling a pilot hole before. The impact driver did it
with ease, and all the screws handled it just fine. The countersink did
exactly what I said as well, not a clean sink, but mostly with some
broken fibers. One of the holes countersunk clean, no clue why.
I didn't try this with a regular drill, might do that next. Impact
drivers I think are easier on the screws, the wood and the guy doing the
driving. They are awesome. They don't un-screw my deck screws though,
snap the heads off those suckers instantly.
--
Jack
Don't believe everything you think!
http://jbstein.com