Brian's Engineering and Science Hotlist. Brian J. Roberts has good directory of basic engineering information links for calculations, components, etc.

CIMWare's Hot Engineering Websites. This is a large, useful directory, but the last update was in June, 2000.

Electro.Patent-Invent.com A great resource to find out about basic electrical and electronic inventions and phenomena. Also has some patent and thesis information.

Engineering Information Center. Maintained by Oak Ridge National Laboratories. Has links to many technical and commercial information sources.

Engineering Resources Online (UK). Reference and standard organizations, patents, institutions, trade organizations, publications, books, journals, software, trade shows, careers, etc.

Engineering Fundamentals (eFunda). Has tutorials and reference information about a wide range of engineering topics, including RP and tooling.

Engineer's Edge. This site has a wide range of tables, specs, formulas, etc., as well as links to breaking news sources for engineering related topics, and a digest of engineering articles.

Steven Henderson's Cutting Edge Designs Site. Has calculators for acceleration, area, force, length, power, pressure, torque, velocity, volume, volumetric flow, weight, temperature, thread & tap guide, metal gage chart, hardness conversion chart, periodic table, units dictionary, currency conversion, etc. Also has an extensive directory section.

icademic.org A portal for electrical, mechanical, biomedical and civil engineering, as well as for life sciences such as agronomy, biochemistry, bioinformatics, biology, biotechnology, botany, chemistry, food science, genetics, microbiology, molecular biology and pharmacology.

iCrank.com. A mechanical engineering portal.

Institution of Mechanical Engineers (UK). Look in the library section for an extensive directory of engineering resources.

Intute: Science, Engineering and Technology Service. Succeeds the Edinburgh Engineering Virtual Library (EEVL) which is no longer available. Extensive engineering references and papers. Also see the TechXtra Service.

Mechanical Design Resource @URLstreet.com. Listings for design publications, patents, design/development, materials links, research, standards, CAD, job/career, etc.

Science.gov A US government portal providing integrated linking and searching of 14 major government scientific and technical sites, such as NASA, Medline and many more. Finds technical papers, news releases, pertinent government web sites, etc.

Society of Manufacturing Engineers (SME). A deep site with good archives.

TenLinks.com. Billed as "The Ultimate Directory for Technology Professionals," editors evaluate and prioritize web technology sites based on merit.