other versions had grains the size of golf and tennis balls for use in 20-inch 51 cm rodman guns. in 1875 dupont introduced hexagonal powder for large artillery, which was pressed using shaped plates with a small center core—about 1.5 inches 3.8 cm diameter, like a wagon wheel nut, the center hole widened as the grain burned.
this lock is conceptually similar to the axis and arc locks but the bearing is instead a ball bearing. tri-ad lock – a locking mechanism exclusively licensed to cold steel. it is a form of lockback which incorporates a thick steel stop pin between the front of the latch and the back of the tang to transfer force from the blade into the handle.
rope is of paramount importance in fields as diverse as construction, seafaring, exploration, sports, theatre, and communications, and has been used since prehistoric times. to fasten rope, many types of knots have been invented for countless uses. citation needed pulleys redirect the pulling force to another direction, and can create mechanical advantage so that multiple strands of rope .
iso 86:1974 steel—tensile testing of sheet and strip less than 3 mm and not less than 0,5 mm thick withdn: replaced with iso 6892-1 iso 89:1974 steel—tensile testing of wire withdn: replaced with iso 6892-1 iso 90 light gauge metal containers—definitions and determination of dimensions and capacities
shuffleboard, more precisely deck shuffleboard, and also known as floor shuffleboard, is a game in which players use cues to push weighted discs, sending them gliding down a narrow court, with the purpose of having them come to rest within a marked scoring area. as a more generic term, it refers to the family of shuffleboard-variant games as a whole
carved stone balls are petrospheres dated from the late neolithic to possibly as late as the iron age mainly found in scotland, but also elsewhere in britain and ireland. they are usually round and rarely oval, and of fairly uniform size at around 2.75 inches or 7 cm across, with 3 to 160 protruding knobs on the surface. they range from having no ornamentation to extensive and highly varied engraved patterns. a wide range of theories have been produced to explain their use or significance, with
one interesting atypical use for bearing balls is at san francisco international airport. the building is supported by 267 columns, each of which rests on a steel ball with a diameter of 5 feet 1.5 m . the ball sits in a concave foundation.
a mirror is an object that reflects light in such a way that, for incident light in some range of wavelengths, the reflected light preserves many or most of the detailed physical characteristics of the original light, called specular reflection.this is different from other light-reflecting objects that do not preserve much of the original wave signal other than color and diffuse reflected .
in the early 1980s, pacific bearing's founder, robert schroeder, invented the first bi-material plain bearing which was size interchangeable with linear ball bearings. this bearing had a metal shell aluminum, steel or stainless steel and a layer of teflon-based material connected by a thin adhesive layer.
tetherball is a game for two opposing players. while not officially recognized as a sport, it is typically an outdoor activity. the equipment consists of a stationary metal pole, from which is hung a volleyball from a rope or tether. the two players stand on opposite sides of the pole.
the following is a list of the four great inventions—as designated by joseph needham 1900–1995 , a british scientist, author and sinologist known for his research on the history of chinese science and technology.
steel wool, also known as iron wool, wire wool, steel wire or wire sponge, is a bundle of very fine and flexible sharp-edged steel filaments. it was described as a new product in 1896. it is used as an abrasive in finishing and repair work for polishing wood or metal objects, cleaning cookware, cleaning windows, and sanding surfaces.
ball-peen hammer heads are typically made of heat treated forged high-carbon steel or alloy steel; it is harder than the face of a claw hammer. softer brass heads are sometimes used. related soft-faced hammers have heads faced with materials such as brass , lead , tightly wound hide , or plastic , although these faces are usually flat, not in a ball or wedge peen shape.