On Mon, 06 Jun 2011 09:18:18 -0500, Jim Yanik
wrote:
A major problem is that neither Phillips or slotted screws were made for
power driving. camout is a big problem. Pozidrive was created to avoid
that,but it never rally took hold. Then came Torx,and that's become more
prevalent,but Philips is still the primary screwhead in use.
Compaq and HP desktop computahs are full of T10 screw heads on 6-32
screws. Just about everything else is Philips. The most common
screws in desktops are 6-32 with a combination 1/4" hex and Philips
drive, and M3 screws with just the Philips head. The larger 6-32
works well with electric screwdrivers. The small M3 will get stripped
out quite easily. Since both will fit a #2 Philips bit, the
temptation to use it on the smaller screws is just too much.
By "small screws",are you referring to screws smaller than 6-32 or similar?
4-40 is a bit small for power driving,but my B&D screwdriver worked OK for
them. a good torque clutch is a necessity.
Nope. 6-32 will mostly work. By mostly, I mean into anything that is
*NOT* screwed into ultra thin soft steel sheet metal, which can be
stripped with little effort. That eliminates many computer cases.
By smaller, I mean the M3 computer case screws and the M2, M2.5, and
M3 laptop screws. For M2 and M2.5, there's just not enough metal in
the head to survive. In addition, they tend to be recessed below the
laptop surface, making it very difficult to extract when stripped.
However, stripping the head is not the most common failure mode. It's
cracking the plastic mount supporting the threaded brass insert.
That's even more difficult to repair, as it usually requires complete
disassembly and glue.
Maybe when commodity electric driver/screwdriver torque limiters are
marked and calibrated in inch-lbs or Newton-meters, like any good
industrial pneumatic screwdriver, I might feel a little better about
using one.
http://www.assemblymag.com/Articles/Feature_Article/d2050b330b5c9010VgnVCM100000f932a8c0____
--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060
http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558