Then one sizes it according to what you want to mount.
I mentioned 2.5x.45 metric... some also use 3 x 0.5mm, but even that's
smaller than 6-32.
If you need to mount through screw insulators (like for mounting a
transistor or a floating-case regulator like an LM-317, you may be hard-
put to find any insulators that will fit even 6-32... metric has more-or-
less filled that market.
On Sun, 5 Apr 2015 09:30:11 -0700 (PDT), walter firstname.lastname@example.org
That has little to do with it. Except for construction and
transportation equipment, it's mostly a matter of whether the industry
is heavily involved with science, in which case US fasteners are
metric fasteners, just as they are everywhere else, or if it has an
international supply chain.
It's useful to look at three markets: the market for off-road
equipment (mining, construction, etc.); the market for automobiles;
and the market for electronic devices.
In the first case, the issues are that the market is truly global and
that the equipment has to be repairable around the world. Thus,
Caterpillar was the first large US company to go 100% metric, beck in
In the case of automobiles, US-built cars have never had much of a
global market but they are now the end of a global *supply chain*. It
is cheaper, and more flexible, to use metric fasteners for US-built
cars, when they may be built from parts supplied by 20 different
Electronic devices are designed and built in an environment that is
close to the underlying science, where metrics have been the lingua
france in the US for most of a century. Metrics are followed in the
engineering and in the assembly; repair is a miniscule economic issue.
Also, the supply chain is not only multinational, but also ad hoc; you
may not know this week where your parts will be coming from next week.
The upshot is that, with 70% of our economy based on domestic
consumption, there is little or no economic advantage to making
sweeping changes to metrics in other industries. Thus, change is slow.
And it has little advantage for anyone other than those industries
The dollar percentage of durable goods sold in the US and made in the
US was 66.6% in 2010. The overall percentage of dollar value of
consumer imports, in all categories including oil, was 11.5%, of which
the actual cost was 7.3%. The remaining 4.2% goes to US
transportation, wholesaling, and retailing markups.
If you follow US manufacturing and trade for a decade or more, you'll
realize that almost every popular conception about our manufacturing
and trade is wrong.
Sure, Steve. It's easy to develop a completely wrong impression about
our trade situation.
BTW, that research piece by the Fed is one of the few you'll see that
analyzes the foreign-made components of products assembled in the U.S.
It's not easy to measure, and off-the-cuff estimates are all over the
map. This one looks like it was done right.
6-32 is a course, ie nc, thread. 8-32 is a fine thread, ie nf. The fine
threads do less cutting relative to the screw's major diameter.
The 8-32 will be less likely to break than the 6-32 which, in steel, is
a consideration. In aluminum probably either one would free of worry.
Maybe the 8-32 would be a little freeer.
Not really, Ig. If your 1/8" drill made an accurately-sized hole, it would
be a VERY slight threadform.... .1380 in a .1250 hole only leaves about 7-
thou of thread engagement. Unless it's only decorative AND the 1/8" drill
is tuned up and used right, that's a 'barely holds' situation.
The called-out tap drill is #36 (0.1065), meaning about 16-thou of thread
engagement, when done right.
1/8" is the specified hole diameter for roll tapping a 6-32. Admittedly,
running a screw in, is not exactly proper thread forming, but in some
situations, should work OK, if loads are low and servicing not likely.
Just as much a factor I'd think, is the probability that the screw crest
will deform due to not being hardened, and I believe this more than the
hole size would reduce the strength.
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