Sunday, 12 June 2011

Tool and cutter grinder

Tool and cutter grinder is used to sharpen milling cutters and tool bits along with a host of other cutting tools.
It is an extremely versatile machine used to perform a variety of grinding operations: surface, cylindrical, or complex shapes. The image shows a manually operated setup, however highly automated Computer Numerical Control (CNC) machines are becoming increasingly common due to the complexities involved in the process.
The operation of this machine (in particular, the manually operated variety) requires a high level of skill. The two main skills needed are understanding of the relationship between the grinding wheel and the metal being cut and knowledge of tool geometry. The illustrated set-up is only one of many combinations available. The huge variety in shapes and types of machining cutters requires flexibility in usage. A variety of dedicated fixtures are included that allow cylindrical grinding operations or complex angles to be ground. The vise shown can swivel in three planes.

The table moves longitudinally and laterally, the head can swivel as well as being adjustable in the horizontal plane, as visible in the first image. This flexibility in the head allows the critical clearance angles required by the various cutters to be achieved.

CNC tool and cutter grinder
Today's tool and cutter grinder is typically a CNC machine tool, usually 4, 5, or 6 axes, which produces endmills, drills, etc. which are widely used in the metal cutting industry.
Modern CNC tool and cutter grinders enhance productivity by typically offering features such as automatic tool loading as well as the ability to support multiple grinding wheels. High levels of automation, as well as automatic in-machine tool measurement and compensation, allow extended periods of unmanned production. With careful process configuration and appropriate tool support, tolerances less than 5 micrometres (0.0002") can be consistently achieved even on the most complex parts.
Apart from manufacturing, in-machine tool measurement using touch-probe or laser technology allows cutting tools to be reconditioned. During normal use, cutting edges either wear and/or chip. The geometric features of cutting tools can be automatically measured within the CNC tool grinder and the tool ground to return cutting surfaces to optimal condition.
Significant software advancements have allowed CNC tool and cutter grinders to be utilized in a wide range of industries. Advanced CNC grinders feature sophisticated software that allows geometrically complex parts to be designed either parametrically or by using third party CAD/CAM software. 3D simulation of the entire grinding process and the finished part is possible as well as detection of any potential mechanical collisions and calculation of production time. Such features allow parts to be designed and verified, as well as the production process optimized, entirely within the software environment.
Tool and cutter grinders can be adapted to manufacturing precision machine components. The machine, when used for these purposes more likely would be called a CNC Grinding System.
CNC Grinding Systems are widely used to produce parts for aerospace, medical, automotive, and other industries. Extremely hard and exotic materials are generally no problem for today's grinding systems and the multi-axis machines are capable of generating quite complex geometries.

Radius grinder
A radius grinder (or radius tool grinder) is a special grinder used for grinding the most complex tool forms, and is the historical predecessor to the CNC tool and cutter grinder. Like the CNC grinder, it may be used for other tasks where grinding spherical surfaces is necessary. The tool itself consists of three parts: The grinder head, work table, and holding fixture. The grinder head has three degrees of freedom. Vertical movement, movement into the workpeice, and tilt. These are generally set statically, and left fixed throughout operations. The work table is a T-slotted X-axis table mounted on top of a radial fixture. Mounting the X axis on top of the radius table, as opposed to the other way around, allows for complex and accurate radius grinds. The holding fixtures can be anything one can mount on a slotted table, but most commonly used is a collet or chuck fixture that indexes and has a separate Y movement to allow accurate depth setting and endmill sharpening. The dressers used on these grinders are usually quite expensive, and can dress the grinding wheel itself with a particular radius.

D-bit grinder
The D-bit grinder is a tool bit grinder that specializes in the grinding of D-bit cutters for pantograph milling machines. Pantographs are a variety of milling machine used to create cavities for the dies used in the molding process, they are being rapidly replaced by CNC machining centers.


Tags: Jig grinder , Surface grinding , Bench grinder , Angle grinder , Centerless grinding , Cylindrical grinder 

Last Friday Night

"Last Friday Night (T.G.I.F.)" is a song by American recording artist Katy Perry. The song was written by Perry, Dr. Luke, Max Martin and Bonnie McKee, and was produced by Dr. Luke and Max Martin. It is the fifth single from Perry's third studio album, Teenage Dream by Capitol. Prior to its single release, "Last Friday Night (T.G.I.F.)" peaked at number sixty-seven on the Billboard Hot 100 and number forty-nine on the Canadian Hot 100 because of digital sales.

Composition
"Last Friday Night (T.G.I.F.)" is apop rock song with a length of three minutes and fifty seconds. It is set in common time and has a moderate tempo of 126 beats per minute. It is written in the key of F♯ major and Perry's vocals span one octave, from C♯4 to D♯5. It follows the chord progression B–G♯m7–D♯m7-C♯. Billboard included the song in their Five Potential Pop Hits for 2011 list.

Artwork
Perry revealed her official album artwork for the 'Last Friday Night (T.G.I.F.)' Remixes! on her Facebook page. The photo features Katy in nerdy gear, including mouth guard and glasses, and was taken when she hosted the Teen Choice Awards in summer 2010. The image is surrounded by '80s-style neon colors and swirly graphics.

Music video and promotion
The music video for "Last Friday Night (T.G.I.F.)" was filmed in May 2011. It will be released on the 14 of June. Perry tweeted, "I told someone about my new music video I just filmed & they responded with 'wow, that's gonna break the internet.' ... Should I knock on wood?" The teaser of the video was released on Perry's Youtube profile on June 7, 2011.
Prior to the video's planned June 14 release date, it was leaked onto the internet June 11. In the video, Perry plays Kathy Beth Terry, a nerdy teenager with braces, headgear and oversized glasses who's just woken up the morning after a house party, surrounding by passed-out partygoers. Puzzled as to what happened, she goes online, only to find pictures of herself in various compromising positions. The video than goes into a flashback of the events that occurred the night before. While studying, Kathy hears loud music from the house next door, and goes over to stop the commotion. She is greeted by the hostess (played by internet celebrity Rebecca Black), who invites her to come in. Another nerdy high schooler, played by Glee star Kevin McHale, oggles her from afar and fantasizes about being with her. Kathy, however is more interested in the attractive football player attending the party, who turns her down because of her appearance. To cheer her up, Black gives Kathy a makeover, ripping off her headgear with pliers, dressing her in tight-fitting neon clothes and teasing her hair out. The jock becomes enamored with her, and everyone starts dancing. Jazz musician Kenny G plays a saxophone solo on the roof while 90's heartthrobs Hanson act as the house band. The entire party ends up moving to Kathy's house, where Kevin McHale's character punches the jock for fondling Kathy. At the end of the night, Kathy finally passes out, and the video shifts to present day, where she looks on with regret.

Critical reception
The song has received mixed to positive reception from music critics. Allmusic picked it among the top tracks on the album, and said that Perry "salutes fellow attention-whore Kesha on “Last Friday Night (T.G.I.F.)”. Rolling Stone said that "Perry likes her songs chatty; in the kegger romp "Last Friday Night," she chirps, "Think I need a ginger ale/That was such an epic fail". Slant Magazine said that “"Last Friday Night (T.G.I.F.)" is a lifeless roller-rink jam with a "T! G! I! F!" shout-along that will no doubt provide the soundtrack to any number of trashy sorority parties this semester". Spin Magazine said that "Last Friday Night recounts an evening of nonstop naughtiness – think streaking, skinny-dipping, and ménage à trois-ing.
Now Magazine said that "The singer recently said that the catchy 'Last Friday Night (T.G.I.F.)' is her version of 'I Gotta Feeling'. With lyrics about photos ending up online after a debauched evening, it’s also reminiscent of Lady Gaga singing about drunkenly losing her keys and phone on Just Dance. Derivative, sure, but the song strikes a perfect equilibrium between Perry’s sex appeal and goofy, self-effacing charm". The A.V. Club said that "assuming that everything here is based on real life also means we have to accept that she’s had a ménage à trois on the indie-rock-meets-American Idol cut Last Friday Night (T.G.I.F.)". The Washington Post said that "Over strummy guitars and zigzagging keyboards, Perry recounts an evening of debauchery with no repercussions, her innocent transgressions (streaking, skinny-dipping) mentioned in the same breath as more serious trouble (mysterious bruises, a blackout), but when it's time for Perry to reflect on her 3 a.m. follies, she stiffly sings, "That was such an epic fail." It sounds like a clueless parent's attempt to speak teenager.

Personnel
Katy Perry – songwriter and vocals
Dr. Luke – songwriter, producer, drums, keyboards and programming
Max Martin – songwriter, producer, drums, keyboards and programming
Bonnie McKee – songwriter
Emily Wright – engineer
Sam Holland – engineer
Tucker Bodine– assistant engineer
Tatiana Gottwald – assistant engineer
Serban Ghenea – mixing
Jon Hanes – mix engineer
Tim Roberts – assistant mix engineer
Lenny Pickett – saxophone
Credits adapted from Teenage Dream album liner notes.

Background
Perry has revealed that she was inspired to write the track, after running naked through a park. According to Music Rooms, Perry claims that after a wild night of partying and streaking, she wrote the song about her antics the next day. Perry revealed: “There’s nothing better than an impromptu dance party with my friends. My track Last Friday Night (T.G.I.F.) is a song about debauchery because I had one of those nights in Santa Barbara. We went out to this place called Wildcat and got crazy,” Perry admitted: “We had a couple of beers and danced until we died, then brought the party back to the hotel room.” She added: “Most of that song is actual truth, apart from the ménage à trois… unfortunately! But, yes, streaking in the park, that’s what we did, so we had to write a song about it the next day!” Bonnie McKee, the co-witer of the song stated "TGIF is pretty much a word for word description of our trip to Santa Barbara [with Perry], so I love that one. It’s really kitschy and fun and makes me nostalgic.

Ethan Allen

Ethan Allen, January 21, 1738  O.S. January 10, 1737– February 12, 1789  was a farmer, businessman, land speculator, philosopher, writer, and American Revolutionary War patriot, hero, and politician. He is best known as one of the founders of the U.S. state of Vermont, and for the capture of Fort Ticonderoga early in the American Revolutionary War.
Born in rural Connecticut, Allen had a frontier upbringing but also received an education that included some philosophical teachings. In the late 1760s he became interested in the New Hampshire Grants, buying land there and becoming embroiled in the legal disputes surrounding the territory. Legal setbacks led to the formation of the Green Mountain Boys, whom Allen led in a campaign of intimidation and property destruction to drive New York settlers from the Grants. When the American Revolutionary War broke out, Allen and the Boys seized the initiative and captured Fort Ticonderoga in May 1775. In September 1775 Allen led a failed attempt on Montreal that resulted in his capture by British authorities. First imprisoned aboard Royal Navy ships, he was paroled in New York City, and finally released in a prisoner exchange in 1778.
Upon his release, Allen returned to the Grants, which had declared independence in 1777, and resumed political activity in the territory. In addition to continuing resistance to New York's attempts to assert control over the territory, Allen was active in efforts by Vermont's leadership for recognition by Congress, and he participated in controversial negotiations with the British over the possibility of Vermont becoming a separate British province.
Allen wrote accounts of his exploits in the war that were widely read in the 19th century, as well as philosophical treatises and documents relating to the politics of Vermont's formation. His business dealings included successful farming operations, one of Connecticut's early iron works, and land speculation in the Vermont territory. Land purchased by Allen and his brothers included tracts of land that eventually became Burlington, Vermont. He was twice married, fathering eight children.

Thomas Young
When he moved to Salisbury, Allen met Thomas Young, a doctor living and practicing just across the provincial boundary in New York. The doctor, only five years older than Allen, taught the younger Allen a great deal about philosophy and political theory, while Allen was able to bring to Young his appreciation of nature and life on the frontier. Young and Allen eventually decided to collaborate on a book intended to be an attack on organized religion, as Young had convinced Allen to become a Deist. They worked on the manuscript until 1764, when Young moved away from the area, taking the manuscript with him.
It was not until many years later, after Young's death, that Allen was able to recover the manuscript. He expanded and reworked the material, and eventually published it as Reason: the Only Oracle of Man.

Moving around
While Heman remained in Salisbury, where he ran a general store until his death in 1778, Ethan's movements over the next few years are poorly documented. He is known to have been living in Northampton, Massachusetts in the spring of 1766, where his son Joseph was born, and where he invested in a lead mine. He was asked to leave Northampton in July 1767 by the authorities; while no official reason is known, biographer Michael Bellesiles suggests that religious differences and Allen's tendency to be disruptive may have played a role in his departure. He then briefly returned to Salisbury before settling in nearby Sheffield, Massachusetts with his younger brother Zimri. It is likely that his first visits to the New Hampshire Grants occurred during these years. While Sheffield would be the family home for ten years, Allen was often absent for extended periods.

New Hampshire Grants
As early as 1749, Benning Wentworth, New Hampshire's governor, was selling land grants in the area west of the Connecticut River, to which New Hampshire had always laid somewhat dubious claim. Many of these grants were sold at relatively low prices to land speculators, with some land kicked back to Wentworth. In 1764, King George issued an order resolving the competing claims of New York and New Hampshire in favor of New York. New York, which had also issued land grants that overlapped some of those sold by Wentworth, insisted that holders of the Wentworth grants pay a fee to New York to have their grants validated. As this fee approached the original purchase price, and many of the holders were land-rich and cash-poor, there was a great deal of resistance to this demand. By 1769 the situation in the Grants had deteriorated to the point where surveyors and other figures of New York authority were being physically threatened and driven from the area.

Allen asked for assistance
A number of the holders of Wentworth grants were originally from northwestern Connecticut, and some of them, including Remember Baker and Seth Warner, were relatives of Allen. In 1770, a group of Wentworth grant holders asked Allen to defend their case before New York's Supreme Court, a move that presented Allen with his first big stage. This move to leadership was not unusual; he was known among his contemporaries to be willing to step forward and take control. The trial, for which Allen hired Jared Ingersoll to represent the grantholder interest, began in July 1770, pitting Allen against politically powerful New York grant-holders, including New York's Lieutenant Governor Colden, James Duane (who was prosecuting the case), and Robert Livingston, the Chief Justice of the Supreme Court (who was presiding over the case). The trial was brief, and the outcome unsurprising, as the court, citing their fraudulently issued nature, refused to allow the introduction of Wentworth's grants as evidence. Before departing for Bennington with the news, Allen was visited by Duane, who offered Allen payments which Duane described in his diary as payment "for going among the people to quiet them". Allen denied taking any money; even if he did, none of his actions appeared to honor Duane's request. According to Allen's account he was outraged, and left his visitors with veiled threats, indicating that attempts to enforce the judgment would be met with resistance.


The Catamount Tavern, late in the 19th century
While many historians have believed that Allen took these actions because he already held Wentworth grants of his own, there is no evidence that he was issued any such grants until after he had been asked to take up the defense of grants held by others. Between May 1770, when he first began working on the defense, and the trial in July, he acquired, for the price of $50, grants from Wentworth to about 1,000 acres (400 ha) of land in Poultney and Castleton.
Green Mountain Boys
On Allen's return to Bennington, the settlers met at the Catamount Tavern to discuss their options. These discussions resulted in the formation of the Green Mountain Boys, with local militia companies in each of the surrounding towns. Allen was named their Colonel Commandant, and cousins Seth Warner and Remember Baker were captains of two of the companies. Further meetings resulted in the creation of committees of safety, and laid down rules by which to resist attempts by the New York provincial government to establish its authority. These included denying surveyors sent by the province the ability to survey any land in the Grants, not just land owned through the Wentworth grants.

While Allen participated in some of the actions to drive surveyors away, he also spent much time exploring the entire territory, probably ranging as far north as the site of Burlington in his wanderings. After selling off some of his Connecticut properties, he began buying wild lands further north in the territory, which he sold at a profit as the southern settlements grew and people began to move further north.
Friction with the provincial government rose notably when, in October 1771, Allen and a company of Boys drove off a group of Scottish settlers near Rupert. Allen detained two of the settlers and forced them to watch the torching of their newly constructed cabins. He then ordered them to leave, saying, "Go your way now, and complain to that damned scoundrel your Governor, God damn your Governor, Laws, King, Council, and Assembly". When the settlers protested his language Allen continued the tirade, threatening to send any troops from New York to Hell. In response, New York's governor, William Tryon, issued warrants for the arrests of those responsible, and eventually put a price of £20 on the heads of six participants, including Allen. Allen and his cohorts countered by issuing offers of their own.

Capture of Fort Ticonderoga
In late April, following the battles of Lexington and Concord, Allen received a message from members of an irregular Connecticut militia that they were planning to capture Fort Ticonderoga, requesting his assistance in the effort. Allen, whether motivated by patriotic impulses (as he describes in his account of the events), or by the realization that the action might improve the political position of his side in the grants disputes, agreed to help, and began rounding up the Green Mountain Boys. On May 2, 60 men from Massachusetts and Connecticut met with Allen in Bennington, where they discussed the logistics of the expedition. By May 7, these men joined Allen and 130 Boys at Castleton. The next morning, Allen was elected to lead the expedition, and a dawn raid was planned for May 10. Two small companies were detached to procure boats, and Allen took the main contingent north to Hand's Cove in Shoreham to prepare for the crossing.

Negotiations with the British
Allen appeared before the Continental Congress as early as September 1778 on behalf of Vermont, seeking recognition as an independent state. He reported that due to Vermont's expansion to include border towns from New Hampshire, Congress was reluctant to grant independent statehood to Vermont. Between 1780 and 1783 Allen participated, along with his brother Ira, Vermont Governor Thomas Chittenden, and others, in negotiations with Frederick Haldimand, the governor of Quebec, that were ostensibly about prisoner exchanges, but were really about establishing Vermont as a new British province and gaining military protection for its residents. The negotiations, once details of them were published, were often described by opponents of Vermont statehood as treasonous, but no such formal charges were ever laid against anyone involved.

Later years
As the war had ended with the 1783 Treaty of Paris, and the United States, operating under the Articles of Confederation, resisted any significant action with respect to Vermont, Allen's historic role as an agitator became less important, and his public role in Vermont's affairs declined.Vermont's government had also become more than a clique dominated by the Allen and Chittenden families due to the territory's rapid population growth.
In 1782, Allen's brother Heber died at the relatively young age of 38. Allen's wife Mary died in June 1783 of consumption, to be followed several months later by their first-born daughter Loraine. While they had not always been close, and Allen's marriage had often been strained, Allen felt these losses deeply. A poem he wrote memorializing Mary was published in the Bennington Gazette.

Publication of Reason
In these years he recovered the manuscript that he and Thomas Young had worked in his youth from Young's widow, who was living in Albany, and began to develop it into the work that was published in 1785 as Reason: the Only Oracle of Man. The work was a typical Allen polemic, but its target was religious, not political. Specifically targeted against Christianity, it was an unbridled attack against the Bible, established churches, and the powers of the priesthood. As a replacement for organized religion, he espoused a mixture of deism, Spinoza's naturalist views, and precursors of Transcendentalism, with man acting as a free agent within the natural world. While historians disagree over the exact authorship of the work, the writing contains clear indications of Allen's style.
On the afternoon of May 9, Benedict Arnold quite unexpectedly arrived on the scene. Flourishing a commission from the Massachusetts Committee of Safety, he asserted his right to command the expedition. The assembled men refused to acknowledge his authority, insisting they would only follow Allen's lead. In a private discussion, Allen and Arnold reached an accommodation, the essence of which was that Arnold and Allen would both be at the front of the troops when the attack on the fort was made.
Around 2 am, a few boats were finally procured for the crossing. However, only 83 men made it to the other side of the lake before Allen and Arnold, concerned that dawn was approaching, decided to attack. In the early dawn, the small force marched on the fort, surprising the lone sentry. Allen went directly to the fort commander's quarters, seeking to force his surrender. Lieutenant Jocelyn Feltham, the assistant to the fort's commander, Captain William Delaplace, was awoken by the noise, and called to wake the captain. Stalling for time, he demanded to know by what authority the fort was being entered. Allen, who later claimed that he said it to Captain Delaplace, said, "In the name of the Great Jehovah and the Continental Congress!" Delaplace finally emerged from his chambers, fully dressed, and surrendered his sword. The rest of the fort's garrison surrendered without firing a shot.

Childhood
Ethan Allen was born in Litchfield, Connecticut, the first-born child of Joseph and Mary Baker Allen. The family moved to Cornwall shortly after his birth. Seven siblings, all of whom survived to adulthood, joined the family between Allen's birth and 1751. His brothers Ira and Heman would also become prominent figures in the early history of Vermont.
Although not very much is known about Allen's childhood, the town of Cornwall was frontier territory in the 1740s. By the time Allen reached his teens, the area, while still a difficult area in which to make a living, began to resemble a town, with wood-frame houses beginning to replace the rough cabins of the early settlers. Joseph Allen died in 1755; at the time of his death he was one of the wealthier landowners in the area, ran a successful farm, and had previously served as town selectman. Allen had, before his father's death, begun studies under a minister in the nearby town of Salisbury with the goal of gaining admission to Yale College. Allen's brother Ira recalled that, even at a young age, Ethan was curious and interested in learning.

Marriage and early adulthood
Allen was forced to end his studies upon his father's death. While he volunteered for militia service in 1757 in response to French movements resulting in the Siege of Fort William Henry, his unit received word while en route that the fort had fallen, and turned back. Even though the French and Indian War continued over the next several years, Allen did not apparently participate in any further military activities, and is presumed to have tended his farm, at least until 1762. In that year, he became part owner of an iron furnace in Salisbury. He also married Mary Brownson, a woman five years his senior, from the nearby town of Roxbury, in July 1762. They first settled in Cornwall, but moved the following year to Salisbury with their infant daughter Loraine. Allen bought a small farm and proceeded to develop the iron works. The expansion of the iron works was apparently costly to Allen; he was forced to sell off portions of the Cornwall property to raise funds, and eventually sold half of his interest in the works to his brother Heman. The Allen brothers sold their interest in the iron works in October 1765.
By most accounts Allen's marriage was an unhappy one. His wife was rigidly religious, prone to criticizing him, and was barely able to read and write. In contrast Allen's behavior was sometimes quite flamboyant, and he maintained an interest in learning. In spite of these differences the marriage survived until Mary's death in 1783. Ethan and Mary had five children together, of whom only two reached adulthood.
Allen's exploits in those years introduced him to the wrong side of the justice system, which would become a recurring feature of his life. In one incident, he and his brother Heman went to the farm of a neighbor, some of whose pigs had escaped onto their land, and seized the pigs. The neighbor sued to have the animals returned to him; Allen pled his own case, and lost. Ethan and Heman were fined ten shillings, and the neighbor was awarded another five shillings in damages. He was also called to court in Salisbury for inoculating himself against smallpox, a procedure that at the time required the sanction of the town selectmen.