Cogwheels

On August 15, 1974 Norway issued a two-stamp set promoting industrial safety. The 1.00 kroner value (Facit #719) of this set depicts a combination turbine and cogwheel.

Here is the 20 pf value (Mi #442) from the Federal Republic of Germany's August 14, 1964 set of three stamps commemorating Prigress in Science and Technology. Stamp commemorates the centenary of Nikolaus Otto's (1832-1891) internal combustion engine.

This set of three "cogwheel" stamps (SG #s 116-8) was issued by Singapore on April 15, 1969 to commemorate the 25th plenary session of the U.N. Economic Commission for Asia and the Far East.

Here is the 60 + 30 (pf) value (Mi #643) from Berlin's "Optical Instruments" semi-postal charity set of April 10, 1981. Stamp depicts a circa 1790 microscope.

Here is Mexico's April 1, 1935 10c stamp (Sc #721) publicizing the country's Industrial Census of April 10, 1935.

On October 9, 1997, Germany issued a set of 5 "Water- and Windmills in Germany" charity stamps. One of the stamps (Mi #1950) shows a German post windmill (ca. 13th century) from the lower Rhineland which features a cutaway showing the gearing arrangement.

Regarding the post windmill, Dr. Obeidat of Philadelphia University (philadelphia.edu.jo) states, "The post or trestle on which the entire mill house rests and around which it revolves, is the main feature of the post windmill...the cog wheel drives the spindle or upright shaft via the smaller horizontal spindle gear, or 'wallower'."

Madagascar
50th Anniversary of International Labor Organization
April 11, 1969
The design includes ILO emblem, cogwheels and wrench.

This September 14, 2000 30 sen value (SG #933) of Malaysia is from a three-stamp set commemorating the 50th anniversary of the Rural and Industrial Development Authority - Council for Indigenous People (RIDA-MARA).

Here is Hong Kong's August 5, 1970 10c stamp (SG #267) commemorating the Asian Productivity Organization's (APO) Asian Productivity Year.

From apo-tokyo.org, "The APO's 10th anniversary is celebrated by declaring 1970 Asian Productivity Year. The first Asian Productivity Congress is held in Tokyo, and the Declaration on Productivity for the Asian Region is declared."