Units of paper quantity and US measure, in some sources, a quire was originally 24 sheets.) Quires of 15, 18 or 20 sheets have also been used, depending on the type of paper. The current word "quire" derives from OE "quair" or "guaer", from OF "quayer", "cayer", (cf. modern Fr. "cahier"), from L. "quaternum", "by fours", "fourfold". Later, when bookmaking switched to using paper and it became possible to easily stitch 5 to 7 sheets at a time, the association of "quaire" with "four" was quickly lost. In the Middle Ages, a quire (also called a "gathering") was most often formed of 4 folded
Drilling formula sheets Drilling formula sheets Drilling Formula Sheets is a set of Drilling Formulas used commonly by drilling engineers in the onshore and offshore oil drilling industry. They are used as part of a key piece of engineering work called Well Control. These formulas are part of the teachings of all well control schools and well engineering schools and for many years have been available from the American Petroleum Institute (API). The formulas from Skynet Labs are currently available in several formats, such as Excel sheets, smart phone app and HTML5 web. The formulas otherwise are available in several well control handbooks.