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Gate Valves Torque Requirements
The operating torque, or turning moment, of a valve depends on the size and characteristics of the valve itself and the type of seat, or surface, on which it rests. Gate valves employ a wedge-shaped gate, or disk, which fits tightly against the seat surfaces in the valve body when the valve is close
How to Make Medieval Pottery
Medieval pottery was made by hand on manually powered wooden pottery wheels. One type, the "pillar wheel," was two circular slabs of wood with small holes carved in the center and placed on either end of a central pole. The two circular slabs were connected by several narrow wooden poles that could
How to Find Partial Sums for Geometric Sequences
When Mark Twain's Tom Sawyer had to paint a fence, he found an easier way to paint: let someone else do it. When a mathematician has an onerous task ahead of him, like summing the terms of a very long sequence, he finds an easier way too: let the sequence itself do it. By analyzing the patterns that
Information on Rare Earth Magnets
The rare-earth magnets are the most powerful permanent magnets currently known. Their applications range from small electric motors to magnetic levitation trains. Understanding the principles of their behavior involves delving into the fundamental forces of the universe.
How to Charge LiPo Cells
Lithium polymer batteries are not to be confused with their more well-known peers, lithium ion, nickel cadmium or nickel metal hydride batteries, and have their own specific charging requirements. A descendant of lithium ion batteries, LiPo batteries contain their electrolyte in solid rather than so
Rare 20th Century Coins
A number of factors can make a coin collectible, valuable or rare. Age can be a major factor; some of the earliest minted coins can be extremely valuable. For a coin dated as recently as the 20th Century to be rare or valuable, it often needs to have been minted erroneously somehow or have an intere
How to Create a Bokken
The bokken, as a wooden katana replica, provides a safer alternative to training with a live, razor-sharp samurai sword. Carving your own bokken provides you with a practice weapon with strengths and weaknesses you know well. You can personalize the bokken to your needs and desires, rather than havi
About Invention Ideas That Haven't Been Done
Since man's beginnings, his imagination has led to innovations, namely, through inventions. Some inventions took off to become successful and changed people's way of living; others, however, remained as ideas, taking an eternal resting place upon the drawing board. History recorded a number of faile
What Years of US Coins Are Worth Saving?
Many U.S. coins that were one time in circulation are worth more than their face value. Always save U.S. coins that are more than a century old, and learn which younger coins are worth saving as well.
What Is the Origin of the Gumdrop Tree?
Native to hot, dry regions of the Southwest, the gumdrop tree -- Ziziphus obtusifolia -- is a often-seen plant in dry hills, scrubland and desert regions. The common name comes from the blue-black berries that appear at the end of the spiny stems. The gumdrop tree is not a shrub for home landscaping
How to Attach a Discone Antenna to a Mast
A discone antenna receives a wide number of bands and frequencies while taking up little space. Resembling upside-down snow cones, these antennas were made to be installed on masts and don't lend themselves well to tower installations. Mounting the antenna is a two-person job.
What Instruments Are Used to Measure Weather?
Measuring and recording weather data requires several pieces of equipment. Comprehensive world weather reporting requires measurements that follow the same guidelines, so weather-monitoring instruments are set up to follow the standards set by the World Meteorological Organization (WMO)....
How Are Lightning Balls Formed?
According to "National Geographic," between 1 in 30 to 150 people have witnessed ball lightning in nature. The phenomenon is described as a tennis ball-sized orb that is electrically charged. Ball lightning spins, bounces, floats and hisses during thunder storms. Ball lightning occurs infrequently a
How to Disassemble a Kel-Tec 9mm
Kel-tec pistols are known for a thin, light-weight design. These pistols come in .32 ACP, .380 and 9 mm calibers. The weapons are made in the United States, and are frequently used as backup guns for police officers, and for civilian concealed carry. Kel-tec pistols are designed similarly, so disass
The Best Way to Tan Hides
If you hunt your own food there are always excess pelts lying around after the meat is cut. Learning how to tan hides is a great way to use as much of the animal as possible. Tanning a hide can be difficult, but with this technique you can get a soft pelt every time.
Experiments on Building an Electromagnet
Building an electromagnet is fun and educational for your children. Gather together a few items such as copper wire, a battery and a nail and you can make a safe electromagnet. During the process you can do a few experiments to illustrate to your children how it works.
How to Make a Solar Panel Out of Household Objects
You can make a simple solar panel in less than an hour with some basic tools found in most garages and toolboxes. Your homemade solar panel won't be from high-density, compressed silicon and will therefore produce much less power than mass-produced silicon panels. But you'll have a panel good enough
How to Measure Iron in Water
While not toxic, the presence of iron in household water can lead to unpleasant odors, stained laundry, discolored water basins and even clogged pipes. However, these symptoms can also be caused by non-ferrous/ferric minerals. To measure the total amount of iron in water, you can use a color-changin
How to Build an Oil Fired Kiln
One of the limitations of creating pottery, either throwing it on a wheel or hand building, is kiln access for firing the pieces. Studio time can be expensive and in some areas, access to kilns is limited or non-existent. Fortunately, innovation and necessity has dictated that kilns can be built rel
Homemade Wind Indicator
A wind indicator, also known as a weather vane, is used to indicate the direction the wind is blowing at any given time. Wind indicators are often seen as architectural ornaments, usually in the form of a cockerel with letters indicating the points of a compass, and are placed at the highest point o