On 2019-02-19 1:21 p.m., Rod Speed wrote:


"Commander Kinsey" wrote in message
news
On Tue, 19 Feb 2019 17:02:54 -0000, Clare Snyder
wrote:

On Tue, 19 Feb 2019 00:15:18 -0500, wrote:

On Mon, 18 Feb 2019 22:46:25 -0500, Clare Snyder
wrote:

On Mon, 18 Feb 2019 19:08:44 -0700, rbowman
wrote:

On 02/18/2019 08:38 AM, Commander Kinsey wrote:
They shouldn't call them self tapping because they rarely do
unless the
wood is very soft indeed.* Usually the force to create the hole
wears
off the er.... the bit the screwdriver goes into.* I almost
always use a
pilot drill first, unless I'm in a hurry, then I curse the bloody
screws
when they burr.

Using the correct size of a quality screwdriver helps. What is the UK
equivalent of Harbor Freight?
"Self drilling" is the term, and if they aren't Chinese junk they are
usually good for 16 guage steel - perhaps 14. Useless foir anything
heavier. Chiners junk is good for about 18 guage aluminum on a good
day.

Actually there are at least four types of screw that cut their own
thread.
You have the self drilling that is a sheet metal screw with a drill
bit tip on the end that actually drills the pilot hole (Commonly
called Tek screws)
Then there is the self tapping sheet metal screw that just has a point
on the end and gnaws it's way in
The third is a "swage form" machine screw that goes into a pilot hole
and the tip is threaded all the way to the end with a slight taper and
a triangular shape until it gets to the body of the thread. It
actually swages threads
The 4th is a self tapping machine screw that has a tapered thread and
slits cut in it to take away the waste material just like a tap.
I have some of each type if anyone wants pictures.
* From the complaint I had pretty much ruled out the common sheet
metal screw with the sharp split tip and the swage form - basically
narrowing it down to the "tek" - but then he complained about it only
working if the "wood" was soft - - - -

*I really think he needs to limit himself to socket head (allen) or
hex head screws - and eventhen he needs to use the correct size
driver.

PZ2 is easier to use.* I'm just saying they shouldn't be sold as "self
tapping" if they really need a pilot hole.

They are called self tappers because they tap the hole.

They arent called self drillers, stupid.

yes they are