18, 1998 Design News
Letters to the Editor
Readers state their views
The breakaway clips break, but...
Regarding "The ultimate portable basketball system"
(Design News, 11/18/96), I have had my Huffy goal &
net up for almost one year. The breakaway clips do break,
and not from the hard use of people hanging on the net.
My son is only 10 years old and could never touch the
net by himself. I think the so-called plastic needs
to be re-evaluated and replaced with a better one. I
feel the sun and cold has managed to weaken the clips.
I don't feel that (having to) replace the clips every
year (makes it) a sound product. Safety should be a
top priority, but durability would get you further in
the long run.
Needs help in a 'big array'
I have an electrically-powered engine, but before a
real-life conditions test can be performed, I need to
get a solar array for the power system. How can I build
one? (A big one!)
--Christopher S. Hedberg,
Purpose of ISO System of limits and fits
The main purpose of the ISO tolerancing system is to
save manufacturing and engineering costs. Hole basis
fits with hole tolerances...help rationalize on standard
cutting tools and gages, whereas shaft basis fits with
shaft tolerances...help rationalize on standard, round
steel bars already available in all major industrial
countries, including the U.S. It does not matter what
type of CAD system engineers use--Pro/ENGINEER, AutoCAD,
SolidWorks, or other--you still have to use standard
holes or shafts in order to save in manufacturing. Engineers
in the EU (European Union) countries have taken advantage
of the system for nearly 60 years, and a lot of users
there still use published tables or memory to arrive
at the required allowance.
The ANSI B4.2 standard shows tables of allowances for
the ISO tolerance zones, and also limits dimensions
for the preferred hole and shaft tolerances shown and
the ANSI first-choice sizes. The tables are also published
in the U.S. (See www.kok.com.prod03.asp) The faster
we can get U.S. engineers to specify the ISO preferred
hole and shaft tolerances on drawings, the sooner we
will save in manufacturing worldwide.
--Knut O. Kverneland
Chairman of ANSI
Y14 Subcommittee 39
The status of Art
What happened to "State of Art"? This is
the first thing I read in Design News and it's not in
the 4/6/98 issue. I hope this is a temporary oversight
and not a permanent deletion.
More links please
I like your Tech Bulletin very much. It would be even
better if it included links to relevant pages. The e-mail
address is nice, but not as valuable in my view.
--Robert M. Braun
Murray Hill, NJ
Spark is the key
Regarding "Shrinking electronics open new opportunities
for powertrain engineers" (Design News, Automotive
Supplement, 1/16/98), I modify and sell spark plugs
that increase engine performance. The practice of the
automotive industry to meet requirements of increased
fuel efficiency and emissions reduction has followed
a path of heavy consumer expense in initial purchase
and maintenance costs.
Engine efficiencies have been seriously impacted by
the fuel additives of alcohol and ether. The sonic spark
plug, which I invented, is improving performance for
a fraction of the cost of most performance upgrades.
It works this way: In the compression/ignition cycle,
ultrasonic acoustics are generated, and amplified in
the combustion process. That accelerates the burn to
improve combustion efficiency in the time window of
The existing automotive spark plug being installed
in new cars is the end of a 100-year-old obsolete design.
Advertisements of "no tune-up required for 100,000
miles" is a sham to hold market share of the service
Yes, there are new opportunities for engineers in the
application of computer electronics to increase performance.
However, the basic element of the whole automotive computer
control system is the technology of combustion. The
burn is the most outer element of any type of combustion
control system. A simple change of spark plug design
is the key element of improved engine performance.
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