A screw is an externally helical threaded fastener capable of being tightened or released by a twisting force ( torque ) to the head . The most common uses of screws are to hold objects together and there are many forms for a variety of materials. Screws might be inserted into holes in assembled parts or a screw may form its own thread. The difference between a screw and a bolt is that the latter is designed to be tightened or released by torquing a nut .
129-598: Romblon ( / r ɒ m ˈ b l oʊ n / , rom- BLOHN , Tagalog: [ɾomˈblon] ), officially the Province of Romblon , is an archipelagic province of the Philippines located in the Mimaropa region . Its main components include Romblon, Romblon , an archipelagic municipality of the same name that also serves as the provincial capital; Tablas , the largest island, covering nine municipalities (including Odiongan ,
258-623: A Cebuano substratum and that many of its words may have been influenced by the later influx of other languages such as Romblomanon. It is spoken in the island municipalities of Banton, Corcuera and Concepcion, as well as in Odiongan and Calatrava in Tablas. Hiligaynon is spoken in municipalities near Capiz and Aklan. As Romblon is part of Mimaropa which is also known as Southwestern Tagalog Region, provincial settlers speak Tagalog/ Filipino as lingua franca between different Visayan languages. The people of
387-417: A female threaded fastener other than a nut. Sheet-metal screws do not have the chip-clearing flute of self-tapping screws. However, some wholesale vendors do not distinguish between the two kinds. A wood screw is a metal screw used to fix wood, with a sharp point and a tapered thread designed to cut its own thread into the wood. Some screws are driven into intact wood; larger screws are usually driven into
516-542: A fish sanctuary and passed laws on fishery. The use of air compressors in the municipal waters was regulated and banned altogether in some municipalities. Marble is the most significant mineral deposit of Romblon and is the most renowned product of the province. Based on statistics, Romblon is the second biggest provincial marble producer of the country next to Bulacan . Romblon marble is of very high quality and comes in shades of white, green, pink, red and black. The Mines and Geosciences Bureau has estimated that Romblon
645-409: A milled slot that commonly requires a tool to transfer the twisting force. Common tools for driving screws include screwdrivers , wrenches , coins and hex keys . The head is usually larger than the body, which provides a bearing surface and keeps the screw from being driven deeper than its length; an exception being the set screw (aka grub screw ). The cylindrical portion of the screw from
774-583: A barangay government is the mandate of the mayor and the Sanggunian of the component city or municipality of which the barangay in question is a part. Provinces are classified according to average annual income based on the previous 4 calendar years. Effective July 29, 2008, the thresholds for the income classes for cities are: A province's income class determines the size of the membership of its Sangguniang Panlalawigan , and also how much it can spend on certain items, or procure through certain means. When
903-631: A fluvial parade featuring the image of the Santo Niño goes around Romblon Bay in order to bring good luck to the villages. A Mardi Gras is also held in the town with various street dancing, food, drinks and music. A similar Biniray Festival also occurs in Banton every 10 September in commemoration of the island's patron, San Nicolas de Tolentino . Other festivals include the Saginyogan Festival in Alcantara,
1032-402: A hole narrower than the screw thread, and cut the thread in the wood. Early wood screws were made by hand, with a series of files, chisels, and other cutting tools, and these can be spotted easily by noting the irregular spacing and shape of the threads, as well as file marks remaining on the head of the screw and in the area between threads. Many of these screws had a blunt end, completely lacking
1161-471: A nearby forge. The screw mill was not a commercial success; it eventually failed due to competition from the lower-cost, gimlet-pointed screw, and ceased operations in 1836. The American development of the turret lathe (1840s) and of automatic screw machines derived from it (1870s) drastically reduced the unit cost of threaded fasteners by increasingly automating the machine-tool control. This cost reduction spurred ever greater use of screws. Throughout
1290-409: A pilot hole in a substrate, and most are classed as screws. Mating threads are formed in the substrate as these fasteners are driven in. Fasteners with a non-tapered shank are generally designed to mate with a nut or to be driven into a tapped hole, and most would be classed as bolts , although some are thread-forming (eg. taptite ) and some authorities would treat some as screws when they are used with
1419-425: A regular province in the same year but due to insufficient income, it became a sub-province of Capiz again from 15 July 1907 until 22 February 1918, when Act No. 2724 reestablished the province. Under Commonwealth Act No. 581, enacted without executive approval on 8 June 1940, the province was reorganized with four towns or municipalities, namely: Tablas (composed of Odiongan , Looc , and Badajoz ), Romblon (including
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#17328512475431548-505: A right-hand screw. For this reason, the left-side pedal of a bicycle has a left-hand thread . The screw mechanism is one of the six classical simple machines defined by Renaissance scientists. Fasteners had become widespread involving concepts such as dowels and pins, wedging, mortises and tenons , dovetails , nailing (with or without clenching the nail ends), forge welding , and many kinds of binding with cord made of leather or fiber, using many kinds of knots . The screw
1677-618: A standard (in about 1841) was the English engineer Sir Joseph Whitworth . Whitworth screw sizes are still used, both for repairing old machinery and where a coarser thread than the metric fastener thread is required. Whitworth became British Standard Whitworth , abbreviated to BSW (BS 84:1956) and the British Standard Fine (BSF) thread was introduced in 1908 because the Whitworth thread was too coarse for some applications. The thread angle
1806-555: A term of three years and limited to three consecutive terms and appoint the directors of each provincial department which include the office of administration, engineering office, information office, legal office, and treasury office. The vice governor acts as the president for each Sangguniang Panlalawigan ( SP ; "Provincial Board"), the province's legislative body. Every SP is composed of regularly elected members from provincial districts, as well as ex officio members. The number of regularly elected SP members allotted to each province
1935-456: A variety of screw head shapes. A few varieties of screw are manufactured with a break-away head, which snaps off when adequate torque is applied, to prevent removal after fitting, often to avoid tampering. The international standards for metric externally threaded fasteners are ISO 898-1 for property classes produced from carbon steels and ISO 3506-1 for property classes produced from corrosion resistant steels. There are many standards governing
2064-441: A very high production rate, and produces virtually no waste material. Slotted head screws require an extra step to cut the slot in the head; this is done on a slotting machine . These machines are essentially stripped down milling machines designed to process as many blanks as possible. The blanks are then polished again prior to threading. The threads are usually produced via thread rolling ; however, some are cut . The workpiece
2193-452: Is 0.25–3 in (6.35–76.20 mm) in diameter . In 1991, responding to an influx of counterfeit fasteners, Congress passed PL 101-592, the "Fastener Quality Act". As a result, the ASME B18 committee re-wrote B18.2.1, renaming finished hex bolts to hex cap screw – a term that had existed in common usage long before, but was now also being codified as an official name for
2322-491: Is 1/4" Whitworth (20 tpi) and for medium/large format cameras is 3/8" Whitworth (16 tpi). It is also used for microphone stands and their appropriate clips, again in both sizes, along with "thread adapters" to allow the smaller size to attach to items requiring the larger thread. Note that while 1/4" UNC bolts fit 1/4" BSW camera tripod bushes, yield strength is reduced by the different thread angles of 60° and 55° respectively. British Association (BA) screw threads, named after
2451-408: Is a misnomer ) or French wood screw (Scandinavia) are large wood screws. Lag screws are used to lag together lumber framing, to lag machinery feet to wood floors, and for other heavy carpentry applications. The attributive modifier lag came from an early principal use of such fasteners: the fastening of lags such as barrel staves and other similar parts. These fasteners are "screws" according to
2580-706: Is a spanner (UK usage) or wrench (US usage), while a nut setter is used with a power screw driver. Modern screws employ a wide variety of screw drive designs , each requiring a different kind of tool to drive in or extract them. The most common screw drives are the slotted and Phillips in the US; hex, Robertson, and Torx are also common in some applications, and Pozidriv has almost completely replaced Phillips in Europe. Some types of drive are intended for automatic assembly in mass-production of such items as automobiles. More exotic screw drive types may be used in situations where tampering
2709-618: Is a lucrative undertaking in Magdiwang. Being an archipelago, Romblon has numerous beaches and dive sites. Among its best white sand beaches are Bonbon, Cobrador and Tiamban Beach in Romblon, Macat-ang, Tabunan and Tambak Beach in Banton, Lunas and Bignay Beach in San Jose, and Cresta del Gallo in San Fernando. The sea surrounding Cresta del Gallo is a famous diving site teeming with marine life. Romblon
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#17328512475432838-596: Is also home to the Tablas Island Blue Hole , the only known blue hole in the Philippines, located in the town of San Agustin. The entrance to the blue hole is a 6-meter (20 ft) wide volcanic chimney, which drops for 20 meters (66 ft) before opening up into the massive chamber below with a total depth of 32 to 40 meters (105–131 ft). Mount Guiting-Guiting in Sibuyan, the province's tallest mountain,
2967-509: Is an ecotourism destination, having been dubbed by some as "the Galápagos of Asia" because it has remained in isolation from the rest of the world since its formation. According to legend, the name "Romblon" was derived from the Romblomanon word Nagalumyom , which pertains to a chicken in the act of sitting on its eggs on a nest. This eventually evolved to Lomlom , and later on to Donblon ,
3096-506: Is autonomous of other provinces within the republic. Each province is governed by two main elected branches of the government: executive and legislative. Judicial affairs are separated from provincial governance and are administered by the Supreme Court of the Philippines . Each province has at least one branch of a Regional Trial Court . The provincial governor is chief executive and head of each province. Provincial governors are elected to
3225-399: Is called a screwdriver . A power tool that does the same job is a power screwdriver ; power drills may also be used with screw-driving attachments. Where the holding power of the screwed joint is critical, torque-measuring and torque-limiting screwdrivers are used to ensure sufficient but not excessive force is developed by the screw. The hand tool for driving hex head threaded fasteners
3354-520: Is considered one of the most difficult climbs in the Philippines, and is thus a major destination of local mountain climbers because of its steep and jagged summit. Another a suitable place for hiking and trekking is Mount Payaopao is Tablas. Meanwhile, Banton's Guyangan Cave System , an Important Cultural Treasure, is where the Banton Cloth — the earliest known warp ikat textile in Southeast Asia —
3483-465: Is determined by its income class. First- and second-class provinces are provided ten regular SP members; third- and fourth-class provinces have eight, while fifth- and sixth-class provinces have six. Exceptions are provinces with more than five congressional districts, such as Cavite with 16 regularly elected SP members, and Cebu , Negros Occidental and Pangasinan which have twelve each. Every SP has designated seats for ex officio members, given to
3612-522: Is elected at an at-large basis and not apportioned through territory-based districts. Those classified as either "highly urbanized" or "independent component" cities are independent from the province, as provided for in Section 29 of the Local Government Code of 1991. Although such a city is a self-governing second-level entity, in many cases it is often presented as part of the province in which it
3741-704: Is endowed with about 150 million metric tons of marble. At current rates of extraction, the supply may last for three more centuries. Tablas Island is also believed to have vast reserves of marble. Marble quarrying and processing are major activities in Romblon. Among the most common marble products are categorized into the following: novelty items (gifts, ashtray, table bars), furniture (dining tables, baptismal fonts) and construction materials (tiles, balusters, marble chips). Other mineral resources with considerable quantity include nickel ore and gold mostly to be found in Sibuyan Island. Gold panning and small-scale mining
3870-402: Is geographically located, or in the case of Zamboanga City , the province it last formed part the congressional representation of . Local government units classified as "component" cities and municipalities are under the jurisdiction of the provincial government. In order to make sure that all component city or municipal governments act within the scope of their prescribed powers and functions,
3999-532: Is historically and geographically part of the Western Visayas Region , is made politically part of the Southern Tagalog Region (Region IV) in the gerrymandering of the Philippines by Ferdinand Marcos on 1972. When Southern Tagalog was divided into Calabarzon and Mimaropa, upon the issuance of Executive Order No. 103 by then-President Gloria Macapagal Arroyo dated May 17, 2002, Romblon
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4128-634: Is limited by the Philippine Constitution. The President of the Philippines however coordinates with provincial administrators through the Department of the Interior and Local Government . For purposes of national representation, each province is guaranteed its own congressional district . One congressional representative represents each district in the House of Representatives . Senatorial representation
4257-459: Is mainly spoken in the town of Romblon, in all of three towns of Sibuyan Island, and the town of San Agustin in Tablas. Onhan is mainly spoken in the municipalities in the southern part of Tablas ( Alcantara , Looc , Ferrol , Santa Fe , San Andres , and Santa Maria ), as well as in the island municipality of San Jose. The northwestern part of Tablas Island (in Odiongan and Calatrava , as well as
4386-427: Is provided to interested clients. Due to the geographical condition of the province, crops and livestock production is generally deficient as compared to the food requirements of Romblon population. To meet the rice requirements, Romblon relies on imports from the neighboring provinces while vegetables, poultry meat, vegetables and fruits are supplied mostly by Luzon. Fishing industry is a major enterprise as Romblon
4515-448: Is surrounded by water on all sides. The fishing grounds of Romblon are a migratory path of fish from Sulu and Visayan Seas passing Tablas Strait , Sibuyan Sea and Romblon Pass. The waters also abound with demersal fish due to the coral reefs surrounding the islands. Because the province has a great potential for aqua-marine development, the province implemented a coastal and resource management program. Each municipality established
4644-609: Is the outer diameter of the thread. The tapped hole (or nut) into which the screw fits, has an internal diameter which is the size of the screw minus the pitch of the thread. Thus, an M6 screw, which has a pitch of 1 mm, is made by threading a 6 mm shank, and the nut or threaded hole is made by tapping threads into a hole of 5 mm diameter (6 mm − 1 mm). Metric hexagon bolts, screws and nuts are specified, for example, in International Standards ISO 4014, ISO 4017, and ISO 4032. The following table lists
4773-423: Is the tensile stress at which the bolt fails. Tensile yield strength is the stress at which the bolt will yield in tension across the entire section of the bolt and receive a permanent set (an elongation from which it will not recover when the force is removed) of 0.2% offset strain . Proof strength is the usable strength of the fastener. Tension testing of a bolt up to the proof load should not cause permanent set of
4902-400: Is then cold headed , which is a cold working process. Heading produces the head of the screw. The shape of the die in the machine dictates what features are pressed into the screw head; for example a flat head screw uses a flat die. For more complicated shapes two heading processes are required to get all of the features into the screw head. This production method is used because heading has
5031-399: Is then tumble finished with wood and leather media to do final cleaning and polishing. For most screws, a coating, such as electroplating with zinc ( galvanizing ) or applying black oxide , is applied to prevent corrosion. Threaded fasteners either have a tapered shank or a non-tapered shank. Fasteners with tapered shanks are designed to either be driven into a substrate directly or into
5160-627: Is undesirable, such as in electronic appliances that should not be serviced by the home repair person. There are many systems for specifying the dimensions of screws, but in much of the world the ISO metric screw thread preferred series has displaced the many older systems. Other relatively common systems include the British Standard Whitworth , BA system (British Association) , and the Unified Thread Standard . The basic principles of
5289-507: Is usually a smaller fastener (less than 1 ⁄ 4 inch (6.35 mm) in diameter) threaded the entire length of its shank that usually has a recessed drive type (slotted, Phillips, etc.), usually intended to screw into a pre-formed thread, either a nut or a threaded (tapped) hole, unlike a wood or self-tapping screw. Machine screws are also made with socket heads (see above), often referred to as socket-head machine screws. ASME standard B18.2.1-1996 specifies hex cap screws whose size range
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5418-816: The Machinery's Handbook criteria, and the obsolescent term "lag bolt" has been replaced by "lag screw" in the Handbook . However, based on tradition many tradesmen continue to refer to them as "bolts", because, like head bolts, they are large, with hex or square heads that require a wrench, socket, or specialized bit to turn. The head is typically an external hex. Metric hex-headed lag screws are covered by DIN 571. Inch square-headed and hex-headed lag screws are covered by ASME B18.2.1. A typical lag screw can range in diameter from 4 to 20 mm or #10 to 1.25 in (4.83 to 31.75 mm), and lengths from 16 to 200 mm or 1 ⁄ 4 to 6 in (6.35 to 152.40 mm) or longer, with
5547-558: The National Capital Region , as well as independent cities , are independent of any provincial government. Each province is governed by an elected legislature called the Sangguniang Panlalawigan and an elected governor . The provinces are grouped into eighteen regions based on geographical, cultural, and ethnological characteristics. Thirteen of these regions are numerically designated from north to south, while
5676-664: The Romblon hawk-owl . In Tablas Island, at least two endemic bird species can be found: the Tablas drongo and Tablas fantail . Romblon comprises 17 municipalities . Of these, nine are located in Tablas Island (San Agustin, Calatrava, San Andres, Odiongan, Ferrol, Santa Fe, Looc, Alcantara and Santa Maria), three in Sibuyan Island (Magdiwang, Cajidiocan and San Fernando) and five (Romblon, San Jose, Banton, Concepcion and Corcuera) are island municipalities. Romblon falls under Type III of
5805-587: The US Third Fleet then stationed east of the Philippines. Units from Company C of the 19th Infantry Regiment, 24th Infantry Division landed on Sawang, Romblon on the night 11 March 1945. By 18 March, the province was liberated from Japanese forces. On July 4, 1946, the United States relinquished sovereignty over the Philippines and recognized the Republic of the Philippines as a sovereign and independent nation with
5934-504: The United States , but is also extensively used in Canada and occasionally in other countries. The size of a UTS screw is described using the following format: X-Y , where X is the nominal size (the hole or slot size in standard manufacturing practice through which the shank of the screw can easily be pushed) and Y is the threads per inch (TPI). For sizes 1 ⁄ 4 inch and larger
6063-412: The industrial revolution . They are key components of micrometers and lathes. There are three steps in manufacturing a screw: heading , thread rolling , and coating . Screws are normally made from wire , which is supplied in large coils, or round bar stock for larger screws. The wire or rod is then cut to the proper length for the type of screw being made; this workpiece is known as a blank . It
6192-443: The screwdriver is in the medieval Housebook of Wolfegg Castle , a manuscript written sometime between 1475 and 1490. However they probably did not become widespread until after 1800, once threaded fasteners had become commodified. Metal screws used as fasteners were rare in Europe before the 15th century, if known at all. The metal screw did not become a common fastener until machine tools for mass production developed toward
6321-410: The 19th century, the most commonly used forms of screw head (that is, drive types ) were simple internal-wrenching straight slots and external-wrenching squares and hexagons. These were easy to machine and served most applications adequately. Rybczynski describes a flurry of patents for alternative drive types in the 1860s through 1890s, but explains that these were patented but not manufactured due to
6450-462: The ASME B18 standard. Lug bolt and head bolts are other terms that refer to fasteners that are designed to be threaded into a tapped hole that is in part of the assembly and so based on the Machinery's Handbook distinction they would be screws. Here common terms are at variance with Machinery's Handbook distinction. Lag screws (US) or coach screws (UK, Australia, and New Zealand) (also referred to as lag bolts or coach bolts , although this
6579-477: The Americans in 1901, Romblon was declared a province and placed under civilian rule. It lost its provincial status for a short while between 1907 and 1945, but regained it in 1946, just after World War II . The inhabitants of Romblon are divided into three ethnolinguistic groups: Romblomanon , Onhan and Asi . These groups occupy specific islands in the province and have their own language and customs. Romblomanon
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#17328512475436708-673: The British Association for Advancement of Science, were devised in 1884 and standardised in 1903. Screws were described as "2BA", "4BA" etc., the odd numbers being rarely used, except in equipment made prior to the 1970s for telephone exchanges in the UK. This equipment made extensive use of odd-numbered BA screws, in order—it may be suspected—to reduce theft. BA threads are specified by British Standard BS 93:1951 "Specification for British Association (B.A.) screw threads with tolerances for sizes 0 B.A. to 16 B.A." While not related to ISO metric screws,
6837-637: The Cantigas River, as well as 34 waterfalls. Sibuyan is commonly known the country as the " Galapagos of Asia" because of its many endemic plant and animal species, some of which have just been discovered recently. Among these endemic species are nine mammals, seven lizards, two amphibians, three birds and 112 vascular plants, such as the Nepenthes argentii , Nepenthes sibuyanensis , Nepenthes armin , Sibuyan striped shrew rat , Sibuyan shrew , Philippine tube-nosed fruit bat , indigo-banded kingfisher , and
6966-467: The Corona climatic classification system which was devised in 1920. It is characterized by no pronounced wet and dry seasons. Generally, the wet season is from June to November and sometimes extends up to December when the southwest monsoon is predominant. The dry season is from January to May but is sometimes interrupted by erratic rainfall. The annual mean temperature is 27 °C (81 °F), with February as
7095-579: The ISO metric screw thread are defined in international standard ISO 68-1 and preferred combinations of diameter and pitch are listed in ISO 261. The smaller subset of diameter and pitch combinations commonly used in screws, nuts and bolts is given in ISO 262 . The most commonly used pitch value for each diameter is the coarse pitch . For some diameters, one or two additional fine pitch variants are also specified, for special applications such as threads in thin-walled pipes. ISO metric screw threads are designated by
7224-595: The Japanese. The movement was led by the Free Panay Guerilla Forces composed of members from the 6th Military District under the direction of Col. Macario Peralta, Jr. One of the major naval engagements during the Battle of Leyte Gulf , the Battle of Sibuyan Sea , happened off the waters of Romblon on 23–24 October 1944 between Japanese Admiral Kurita ’s fleet from Singapore and Admiral Halsey 's carrier planes from
7353-497: The Local Government Code mandates the provincial governor to review executive orders issued by mayors, and the Sangguniang Panlalawigan to review legislation by the Sangguniang Panlungsod (City Council) or Sangguniang Bayan (Municipal Council), of all component cities and municipalities under the province's jurisdiction. The provincial government does not have direct relations with individual barangays. Supervision over
7482-894: The National Capital Region, the Cordillera Administrative Region , the Southwestern Tagalog Region (Mimaropa), the Negros Island Region , and the Bangsamoro Autonomous Region in Muslim Mindanao are only designated by acronyms. Each province is a member of the League of Provinces of the Philippines , an organization that aims to address issues affecting provincial and metropolitan government administrations. A provincial government
7611-527: The National Museum. The town also has colonial-era bridges that were declared Important Cultural Treasures. A similar fort in Banton, the centuries-old Fort San Jose and Banton Church , were built in the 1600s and was also used as defenses against Muslim pirates. Every second week of January, Romblon town celebrates the feast of the Santo Niño de Cebú, also known as the Biniray Festival. In that week,
7740-487: The Sanrokan Festival in Banton, and Looc's Talabukon Festival , which honors the giant genie-like epic hero, Talabukon, who saved the people from pirates. In recent years Romblon Island has attracted more scuba divers. It has pristine and untouched reefs with almost undisturbed hard and soft corals around the islands of Romblon, Logbon, Alad and Cobrador. With multiple marine sanctuaries and private associations most of
7869-521: The Spanish claimed to have observed the screw-like shape of Romblon Island. Meanwhile, Reyes claims Romblon originated from " doubloon ", which refers to the Spanish coin used by Moro pirates in paying dowries for their brides-to-be. The Spanish might have named the island after the shape of the coin. Romblon's aboriginal inhabitants were the Negritos from Panay and Mangyans from Mindoro , who settled in
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#17328512475437998-417: The United States acquired the Philippines from Spain in 1898, the islands were divided into four gobiernos (governments), which were further subdivided into provinces and districts. The American administration initially inherited the Spanish divisions and placed them under military government. As insurgencies were pacified, civil government was gradually organized. Screw The screw head on one end has
8127-475: The United States are still inch based. The numbers stamped on the head of the bolt are referred to the grade of the bolt used in certain application with the strength of a bolt. High-strength steel bolts usually have a hexagonal head with an ISO strength rating (called property class ) stamped on the head. And the absence of marking/number indicates a lower grade bolt with low strength. The property classes most often used are 5.8, 8.8, and 10.9. The number before
8256-495: The Visayas to expand the recognition of his revolutionary government in the central and southern Philippines. The Katipunan general Mariano Riego de Dios and his forces liberated Romblon, while generals Ananias Diocno and Leandro Fullon proceeded to Panay. On 25 July the same year, Riego de Dios took the Romblon capital and captured Spanish officials. Four days later, the Spanish politico-military governor Don Carlos Mendoza formally signed
8385-458: The arrival of the Spanish in 1569. Archaeological artifacts recovered by the National Museum in 1936 indicate that the aborigines of Romblon have a rich and advanced culture. During the Spanish colonial rule, Romblon was initially administered under the province of Arevalo (Iloilo) until 1716, when it was transferred to the jurisdiction of the newly created province of Capiz . With arrival of
8514-413: The bolt and should be conducted on actual fasteners rather than calculated. If a bolt is tensioned beyond the proof load, it may behave in plastic manner due to yielding in the threads and the tension preload may be lost due to the permanent plastic deformations. When elongating a fastener prior to reaching the yield point, the fastener is said to be operating in the elastic region; whereas elongation beyond
8643-400: The bows screwed to the frame with 00-72 (pronounced double ought – seventy two) size screws. To calculate the major diameter of "ought" size screws count the number of 0's and multiply this number by 0.013 and subtract from 0.060. For example, the major diameter of a 000-72 screw thread is .060 – (3 x .013) = 0.060 − 0.039 = .021 inches. For most size screws there are multiple TPI available, with
8772-668: The central section of the island. The highest elevation is almost 500 meters (1,600 ft) above sea level. Sibuyan Island is a thickly forested mountain mass. The western portion of the island may be characterized as extensively rugged, having ascents of 60 percent or more while the eastern section is relatively undulating to rolling. The highest elevation, the peak of Mt. Guiting-Guiting, reaches about 2,058 meters (6,750 feet) above sea level. The major areas that are highly productive and buildable are basically in Tablas and Sibuyan. These include Odiongan, San Andres, Looc and Santa Fe in Tablas Island. All three municipalities in Sibuyan Island, on
8901-445: The coarse threads of a wood-screw or sheet-metal-screw threadform (but larger). The materials are usually carbon steel substrate with a coating of zinc galvanization (for corrosion resistance). The zinc coating may be bright yellow (electroplated), or dull gray ( hot-dip galvanized ). Bone screws have the medical use of securing broken bones in living humans and animals. As with aerospace and nuclear power, medical use involves some of
9030-507: The coldest month with temperatures dropping to 20 °C (68 °F), and May as the warmest month with temperatures reaching up to 35 °C (95 °F). Habagat monsoon winds pass through the province from June to October while northeasterly winds or Amihan blows through the islands from December to February. The population of Romblon in the 2020 census was 308,985 people, with a density of 200 inhabitants per square kilometer or 520 inhabitants per square mile, ranking it fourth among
9159-437: The difficulties and expense of doing so at the time. In 1908, Canadian P. L. Robertson was the first to make the internal-wrenching square socket drive a practical reality by developing just the right design (slight taper angles and overall proportions) to allow the head to be stamped easily but successfully, with the metal cold forming as desired rather than being sheared or displaced in unwanted ways. Practical manufacture of
9288-757: The directors of each provincial department, which include the office of administration, engineering office, information office, legal office, and treasury office. As of 30 June 2019, the incumbent governor of Romblon is Jose "Otik" Riano, from the PDPLBN . He was elected in 2013 as vice-governor and reelected in 2016. Provinces of the Philippines In the Philippines , provinces ( Filipino : lalawigan or probinsiya ) are one of its primary political and administrative divisions . There are 82 provinces at present, which are further subdivided into component cities and municipalities . The local government units in
9417-413: The end of the 18th century. This development blossomed in the 1760s and 1770s. along two separate paths that soon converged : The first path was pioneered by brothers Job and William Wyatt of Staffordshire , UK, who patented in 1760 a machine that one might today best call a screw machine of an early and prescient sort. It made use of a leadscrew to guide the cutter to produce the desired pitch, and
9546-523: The end of the Spanish rule in 1898. As a sub-province, Romblon was under an army officer with the rank of captain. The town of Romblon was its capital and the other municipalities were Azagra, Badajos (now San Agustin), Banton, Cajidiocan, Corcuera, Looc, Magallanes (now Magdiwang), Odiongan, Despujols (now San Andres) and Santa Fe. In 1898, amid the Philippine Revolution , Katipunan leader Emilio Aguinaldo sent his generals to several provinces in
9675-435: The first census of the islands. In 1635, Augustinian Recollect missionaries arrived in Romblon to establish Catholic missions and settlements. They helped the Spanish authorities establish peace and order in the islands. In 1868, they established seven missionary centers at Romblon, Badajoz (San Agustin), Cajidiocan, Banton, Looc, Odiongan and Magallanes (Magdiwang). They also built massive forts, churches and watchtowers in
9804-608: The five provinces of Mimaropa in terms of population with 9.9 percent of the region's population. San Jose and Romblon are the two most-densely populated municipalities in the province at 490/km and 450/km, respectively. Cajidiocan is the least densely populated municipality at 110/km. Males outnumber females in the province with a sex ratio of 102:100 according to the 2010 census. Of the province's 283,482 household population, males accounted for 144,091 or 50.8 percent while females made up 139,391 or 49.2 percent. The voting-age population (18 years old and over) accounted for 56.6 percent of
9933-495: The frequently pass through the province yearly. Agriculture is the main industry in Romblon. Coconut is the most cultivated crop with a total planted area of 58,270.44 hectares (224.9834 sq mi). San Agustin has the most extensive area with coconut plants followed by Romblon and Cajidiocan. Rice is the next crop, cultivated particularly in Odiongan, Looc, Cajidiocan and Santa Fe. Other crops grown include root crops, vegetables and fruits. Odiongan, Banton and Magdiwang have
10062-535: The greatest areas planted with root crops and correspondingly, have the highest volume of production. Vegetable production is mostly for home consumption and grown in small scale. Livestock development and poultry production is a viable small scale enterprise for farmers in the province. The provincial government maintains breeding facilities in strategic locations province-wide to encourage farmers to engage in livestock and poultry production to augment their income. Livestock and poultry management training and seminars
10191-409: The highest technology for fasteners; excellent performance, longevity, and quality are required, and reflected in prices. Bone screws are often made of relatively non-reactive stainless steel or titanium, and they often have advanced features such as conical threads, multistart threads, cannulation (hollow core), and proprietary screw drive types, some not seen outside of these applications. There are
10320-552: The household population of the province in 2010, up from 52.7 percent in 2000. There were more females (50.2 percent) than males (49.8 percent) among the voting age population. The languages of Romblon, as well as all languages native to the Philippines, belong to the Austronesian language family , the second largest language family in the world with 1,257 known languages, second only to the Niger–Congo family's 1,538 languages. All of
10449-589: The influx of Hiligaynon , Aklanon , Bicolano and Tagalog migrants as early as 1870. According to historians Emma Helen Blair and James Alexander Robertson , the Spanish arrived in Romblon in 1569 led by conquistador Martin de Goiti who was dispatched by Miguel López de Legazpi to explore the western and northern portion of the Visayas region including Romblon and Mindoro. The islands were later organized into three encomiendas and were administered from Arevalo . De Loarca visited Romblon in 1582 and conducted
10578-479: The internal-wrenching hexagon drive ( hex socket ) shortly followed in 1911. In the early 1930s American Henry F. Phillips popularized the Phillips-head screw , with a cross-shaped internal drive. Later improved -head screws were developed, more compatible with screwdrivers not of the exactly right head size: Pozidriv and Supadriv . Phillips screws and screwdrivers are to some extent compatible with those for
10707-604: The islands during the precolonial period. Ancient wooden coffins discovered in the Guyangan Cave System of Banton Island in 1936 signify a rich ancient civilization and culture in the province before the arrival of the Spaniards in 1569. These artifacts are currently on display at the National Museum in Manila . Remnants of Negrito and Mangyan aborigines now live in the mountains of Tablas and Sibuyan after they were displaced by
10836-550: The islands municipalities of Corcuera, Banton, and Concepcion), speaks the Asi language. The province relies on agriculture , particularly rice and copra farming as well as fishing , for its livelihood. It also has a lucrative marble industry due to an abundance of Italian-quality marble, hence, its moniker as the "Marble Capital of the Philippines." The islands of the province have a number of white sand beaches, diving spots, mountains and rainforests that tourists visit. Sibuyan island
10965-482: The islands of Logbon, Cobrador and Alad), Maghali (comprising Banton , Corcuera , and Concepcion ), and Sibuyan (composed of the towns of Cajidiocan , Magdiwang and San Fernando ). During World War II , the Japanese Imperial Forces established a garrison in Romblon on 21 March 1942 which they maintained until the end of the war. The islands became one of the centers of resistance movement against
11094-429: The islands. Romblon Island is hilly with a maximum elevation of about 400 meters (1,300 ft) above sea level. Tablas Island shows varied relief characteristics. The western coastal areas are level to undulating while the eastern coastal areas are rough to rugged. The southern section covering Santa Fe and the mid-western portion may be described as having rolling to rough terrain. Extremely rugged areas can be found in
11223-546: The languages of the Philippines, except Samalan, are classified as Philippine languages under the Western Malayo-Polynesian branch of Austronesian. The Philippine language group has three main branches: Northern , Southern and Central , the latter of which is composed of the Bisayan , Bikol and Tagalog languages . Unlike other islands or provinces in the Philippines where all local languages are classifiable under
11352-431: The largest municipality in the province); Sibuyan with its three towns; as well as the smaller island municipalities of Corcuera , Banton , Concepcion , San Jose . The province lies south of Marinduque and Quezon , east of Oriental Mindoro , north of Aklan and Capiz , and west of Masbate . According to the 2020 census, it has a total population of 308,985. Romblon was inhabited by aboriginal Filipinos prior to
11481-410: The letter M followed by the major diameter of the thread in millimetres (e.g. M8 ). If the thread does not use the normal coarse pitch (e.g. 1.25 mm in the case of M8), then the pitch in millimeters is also appended with a multiplication sign (e.g. "M8×1" if the screw thread has an outer diameter of 8 mm and advances by 1 mm per 360° rotation). The nominal diameter of a metric screw
11610-483: The machinist happened to need on any given day). In 1821 Hardman Philips built the first screw factory in the United States – on Moshannon Creek, near Philipsburg – for the manufacture of blunt metal screws. An expert in screw manufacture, Thomas Lever, was brought over from England to run the factory. The mill used steam and water power, with hardwood charcoal as fuel. The screws were made from wire prepared by "rolling and wire drawing apparatus" from iron manufactured at
11739-573: The marine life around Romblon is protected. In addition to the reefs, Romblon has been becoming famous for its rare and unique macro habitat, such as the Melibe colemani , the Cyerce nigra and the Cyerce bourbonica . Just like any other province in the Philippines, Romblon's chief executive and head is the provincial governor. Elected to a term of three years and limited to three consecutive terms, he or she appoints
11868-406: The mass production of screws continued to push unit prices lower and lower for decades to come, throughout the 19th century. The mass production of wood screws (metal screws for fixing wood) in a specialized, single-purpose, high-volume-production machine tool; and the low-count, toolroom -style production of machine screws or bolts (V-thread) with easy selection among various pitches (whatever
11997-405: The material and mechanical properties of imperial sized externally threaded fasteners. Some of the most common consensus standards for grades produced from carbon steels are ASTM A193, ASTM A307, ASTM A354, ASTM F3125, and SAE J429. Some of the most common consensus standards for grades produced from corrosion resistant steels are ASTM F593 & ASTM A193. The hand tool used to drive in most screws
12126-632: The most common being designated a Unified Coarse Thread (UNC or UN) and Unified Fine Thread (UNF or UF). Note: In countries other than the United States and Canada, the ISO Metric Screw Thread System is primarily used today. Unlike most other countries the United States and Canada still use the Unified (Inch) Thread System. However, both are moving over to the ISO Metric System. It is estimated that approximately 60% of screw threads in use in
12255-487: The municipality of San Agustin in Tablas Island. Onhan, on the other hand, belongs to the Western Visayan subgroup, which includes Kinaray-a and Aklanon , as well as several minor languages spoken on Mindoro, Palawan, and some small islands in between. Its speakers are mainly from the southern portion of Tablas Island, in the municipalities of San Andres, Santa Maria, Alcantara, Ferrol, Looc, and Santa Fe, as well as in
12384-536: The municipality of San Jose in Carabao Island. Finally, Asi is not classified under any specific subgroup of Visayan, and instead makes up its own immediate branch of Visayan. David Paul Zorc, a linguist from the Australian National University whose expertise is on Philippine languages, notes that Asi speakers may have been the first Visayan speakers in the region. He also suggests that Asi may have
12513-473: The name reported by Spanish chronicler Miguel de Loarca in his book Relacion de las Islas Filipinas in 1582, before finally evolving to Romblon. Meanwhile, local historians Roland Madeja and Evelyn Reyes relate the origin of the name "Romblon" to the shape of Romblon Island. Madeja claims that the name was derived from the Spanish word ronblon , another term for tornillo , meaning " screw ." According to him,
12642-502: The newer types, but with the risk of damaging the heads of tightly fastened screws. Threadform standardization further improved in the late 1940s, when the ISO metric screw thread and the Unified Thread Standard were defined. Precision screws, for controlling motion rather than fastening, developed around the turn of the 19th century, and represented one of the central technical advances, along with flat surfaces, that enabled
12771-503: The notion that Maudslay had invented the slide rest, but this was incorrect; however, his lathes helped to popularize it. These developments of the 1760–1800 era, with the Wyatts and Maudslay as arguably the most important drivers, caused great increase in the use of threaded fasteners. Standardization of threadforms began almost immediately, but it was not quickly completed; it has been an evolving process ever since. Further improvements to
12900-400: The other hand, have substantial level to gently sloping lands. Overall, good developable lands represent about 13 percent of the province's total area. Romblon, particularly Sibuyan Island, is among the few places in the Philippines with a well-preserved natural environment. Uninterrupted rainforest covers 75 percent of the island. It is also home to the country's cleanest inland body of water,
13029-444: The point is the ultimate tensile strength in MPa divided by 100. The number after the point is the multiplier ratio of yield strength to ultimate tensile strength. For example, a property class 5.8 bolt has a nominal (minimum) ultimate tensile strength of 500 MPa, and a tensile yield strength of 0.8 times ultimate tensile strength or 0.8 (500) = 400 MPa. Ultimate tensile strength
13158-570: The population. Poverty incidence of Romblon Source: Philippine Statistics Authority Romblon used to be one of the poorest provinces in the Philippines until 2015 when it recorded lower poverty incidence of 38.63 percent, according to the Philippine Statistics Authority . Poverty incidence in the province further declined to 28.28 percent in 2018. The provincial economy is heavily reliant on agriculture, tourism and mineral extraction which can be greatly affected by typhoons
13287-473: The province are predominantly Roman Catholic . In 2012, the UP School of Economics reported that 75 percent of households were Catholic (Roman Catholic and Iglesia Filipina Independiente combined), 9 percent were Muslim and 3-5 percent belonged to Iglesia ni Cristo . Another governmental source reported in 2011 that Mainline Protestants and Evangelicals then formed a significant minority of up to 8% of
13416-470: The province, such as Fort San Jose in Banton and Fort San Andres in Romblon, following a Dutch attack in 1646 which destroyed the capital town and to repulse recurring Moro raids. Romblon was separated from the jurisdiction of Arevalo and annexed to Capiz , when the province was created in 1716. More than a century later in 1850, the inhabitants of the province began using Spanish family names after governor-general Narciso Clavería decreed on 21 November 1849
13545-399: The relationship given in these standards between the thread size and the maximum width across the hexagonal flats (wrench size): In addition, the following non-preferred intermediate sizes are specified: Bear in mind that these are just examples and the width across flats is different for structural bolts, flanged bolts, and also varies by standards organization. The first person to create
13674-470: The respective local presidents of the Association of Barangay Captains (ABC), Philippine Councilors' League (PCL), and Sangguniang Kabataan ( SK ; "Youth Council"). The vice governor and regular members of an SP are elected by the voters within the province. Ex officio members are elected by members of their respective organizations. National intrusion into the affairs of each provincial government
13803-418: The rolling process does not cut the grain of the metal. A self-tapping screw is designed to cut its own thread, usually in a fairly soft metal or plastic, in the same way as a wood screw (wood screws are actually self-tapping, but not referred to as such). ASME standards specify a variety of machine screws (aka stove bolts ) in diameters ranging up to 0.75 in (19.05 mm). A machine screw or bolt
13932-498: The same diameter and pitch as ISO M6, the threads have different forms and are not compatible. BA threads are still common in some niche applications. Certain types of fine machinery, such as moving-coil meters and clocks, tend to have BA threads wherever they are manufactured. BA sizes were also used extensively in aircraft, especially those manufactured in the United Kingdom. BA sizing is still used in railway signalling, mainly for
14061-593: The same subgroup of languages, each of the three languages of Romblon — Romblomanon, Onhan and Asi — actually belongs to a different subgroup of the Visayan language group. Romblomanon belongs to the Central Visayan subgroup, which spans from Waray-Waray in Samar and Leyte , through Masbatenyo and Sorsoganon , and as far west as Hiligaynon and Capiznon on Panay . It is spoken in Romblon and Sibuyan Islands, as well as in
14190-748: The sharp tapered point on nearly all modern wood screws. Some wood screws were made with cutting dies as early as the late 1700s (possibly even before 1678 when the book content was first published in parts). Eventually, lathes were used to manufacture wood screws, with the earliest patent being recorded in 1760 in England. During the 1850s, swaging tools were developed to provide a more uniform and consistent thread. Screws made with these tools have rounded valleys with sharp and rough threads. Once screw turning machines were in common use, most commercially available wood screws were produced with this method. These cut wood screws are almost invariably tapered, and even when
14319-637: The signing of the Treaty of General Relations and Protocol by representatives of the United States and Republic of the Philippines. On 1 October 1946, Congress passed Republic Act No. 38, sponsored by Cong. Modesto Formilleza, which abolished the four special municipalities and restored Romblon and its municipalities to its pre-war status. In the decades that followed, the province saw the creation of new municipalities, such as Alcantara (1961) from Looc, Calatrava (1969) from San Agustin, Ferrol (1978) from Odiongan, and Santa Maria (1984) from San Agustin. Romblon, which
14448-495: The size is given as a fraction; for sizes less than this an integer is used, ranging from 0 to 16. The integer sizes can be converted to the actual diameter by using the formula 0.060 + (0.013 × number). For example, a #4 screw is 0.060 + (0.013 × 4) = 0.060 + 0.052 = 0.112 inches in diameter. There are also screw sizes smaller than "0" (zero or ought). The sizes are 00, 000, 0000 which are usually referred to as two ought, three ought, and four ought. Most eyeglasses have
14577-563: The sizes were actually defined in metric terms, a 0BA thread having a 6 mm diameter and 1 mm pitch. Other threads in the BA series are related to 0BA in a geometric series with the common factors 0.9 and 1.2. For example, a 4BA thread has pitch p = 0.9 4 {\displaystyle \scriptstyle p=0.9^{4}} mm (0.65 mm) and diameter 6 p 1.2 {\displaystyle \scriptstyle 6p^{1.2}} mm (3.62 mm). Although 0BA has
14706-513: The slot was cut with a rotary file while the main spindle held still (presaging live tools on lathes 250 years later). Not until 1776 did the Wyatt brothers have a wood-screw factory up and running. Their enterprise failed, but new owners soon made it prosper, and in the 1780s they were producing 16,000 screws a day with only 30 employees —the kind of industrial productivity and output volume that would later become characteristic of modern industry but which
14835-409: The south. It is approximately 187 nautical miles (346 km) and 169 miles (272 km) south of Manila. The islands are dispersed and accessible only via sea transportation except for Tablas Island where a domestic airport is located in the municipality of Alcantara. The province has a total land area of approximately 1,533.45 square kilometers (592 sq mi) representing about 5.3 percent of
14964-482: The surrender of Romblon's district government, ending more than three hundred years of Spanish rule in the archipelagic province. Later, Don Wenceslao Molo, a local from Romblon town, was appointed governor and became responsible for the collection of a total amount of ₱ 22,765.21 , Romblon's share to the war expenditures of the Revolutionary Government from 31 May 1898 to 28 February 1899. A local election
15093-426: The tapered shank is not obvious, they can be discerned because the threads do not extend past the diameter of the shank. Such screws are best installed after drilling a pilot hole with a tapered drill bit. The majority of modern wood screws, except for those made of brass, are formed on thread rolling machines. These screws have a constant diameter and threads with a larger diameter than the shank and are stronger because
15222-481: The termination of electrical equipment and cabling. BA threads are extensively used in Model Engineering where the smaller hex head sizes make scale fastenings easier to represent. As a result, many UK Model Engineering suppliers still carry stocks of BA fasteners up to typically 8BA and 10BA. 5BA is also commonly used as it can be threaded onto 1/8 rod. The Unified Thread Standard (UTS) is most commonly used in
15351-402: The total land area of Region IV-B Mimaropa . It is generally mountainous with about 40 percent of its land area having an inclination of more than 50 percent. Only four percent of the total area has an inclination of three to eight percent, while a sparse 10 percent has an inclination of three to zero percent. Narrow strips of coastal lowlands, low hills and plains typify the topography of some of
15480-428: The trifecta of leadscrew, slide rest, and change-gear gear train, all in the right proportions for industrial machining. In a sense he unified the paths of the Wyatts and Ramsden and did for machine screws what had already been done for wood screws, i.e., significant easing of production spurring commodification . His firm remained a leader in machine tools for decades afterward. A misquoting of James Nasmyth popularized
15609-413: The underside of the head to the tip is called the shank ; it may be fully or partially threaded with the distance between each thread called the pitch . Most screws are tightened by clockwise rotation, which is called a right-hand thread . Screws with a left-hand thread are used in exceptional cases, such as where the screw will be subject to counterclockwise torque , which would tend to loosen
15738-609: The use of surnames from the Catálogo alfabético de apellidos . Asi -speaking natives were assigned the letter F, Romblomanon speakers were assigned the letter M, speakers of the Sibuyanon style of Romblomanon were assigned the letter R, while Onhan -speaking natives were assigned the letter G. In 1853, the islands were organized into a politico-military comandancia ("sub-province" in English) administered from Capiz and continued to be so until
15867-406: The yield point is referred to as operating in the plastic region of the bolt material. If a bolt is loaded in tension beyond its proof strength, the yielding at the net root section of the bolt will continue until the entire section begins to yield and it has exceeded its yield strength. If tension increases, the bolt fractures at its ultimate strength. Mild steel bolts have property class 4.6, which
15996-405: Was 55°, and the depth and pitch varied with the diameter of the thread (i.e., the bigger the bolt, the coarser the thread). Spanners for Whitworth bolts are marked with the size of the bolt, not the distance across the flats of the screw head. The most common use of a Whitworth pitch nowadays is in all UK scaffolding . Additionally, the standard photographic tripod thread, which for small cameras
16125-466: Was also held in Romblon town for its ministers of justice and barrio officials. However, Molo's term was a brief transition to another era as the Americans arrived in the province a few months later. Upon the restoration of peace and order in the province following the Philippine–American War , the Americans established civilian government in the islands on 16 March 1901. Romblon was created as
16254-625: Was found in 1936. Aside from the precolonial Guyangan Cave System in Banton, the province also has several heritage sites built during the Spanish colonial period. In Romblon town, the forts of San Andres and Santiago served as fortifications against Muslim pirates in the 17th century, while the St. Joseph Cathedral and Belfry houses a centuries-old image of the Santo Niño de Cebú or the Holy Child. Both heritage sites were declared National Cultural Treasures by
16383-468: Was made part of Mimaropa, officially Southwestern Tagalog Region. Romblon is strategically situated at the center of the Philippine archipelago . Geographically part of the Visayas , it is composed of three major islands (Tablas, Sibuyan and Romblon) and 17 smaller islands. It is surrounded by deep waters, and is bounded by Masbate in the east, Mindoro in the west, Marinduque in the north and Panay in
16512-790: Was one of the last of the simple machines to be invented. It first appeared in Mesopotamia during the Neo-Assyrian period (911-609) BC, and then later appeared in Ancient Egypt and Ancient Greece where it was described by the Greek mathematician Archytas of Tarentum (428–350 BC). By the 1st century BC, wooden screws were commonly used throughout the Mediterranean world in screw presses for pressing olive oil from olives and for pressing juice from grapes in winemaking . The first documentation of
16641-406: Was revolutionary at the time. Meanwhile, English instrument-maker Jesse Ramsden (1735–1800) was working on the toolmaking and instrument-making end of the screw-cutting problem, and in 1777 he invented the first satisfactory screw-cutting lathe . The British engineer Henry Maudslay (1771–1831) gained fame by popularizing such lathes with his screw-cutting lathes of 1797 and 1800, containing
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