Dorsey’s most popular model of optical comparator, now featuring new look.

16H Optical Comparator

16H Optical Comparator Key Features:

• 16” high resolution vertical glass screen for optimum viewing of the erect profile image.
• Machined chart ring with recessed screen protects internal optics and facilitates the alignment of the screen to the optical axis.
• Large format vernier protractor with one minute graduations.
• Quick change single lens mount with choice of lenses: 10X, 20X, 25X, 31.25X, 50X, 62.5X, & 100X.
• Coated telecentric par focal optics.
• Choice of fiber optic or LED surface illumination.
• Nickel plated cast iron workstage 18” X 5” with universal dovetail slot.
• Stage travel is 10” x-axis and 6” y-axis and 2” focus.
• Crossed roller bearing table travel in all axes.
• X & Y axis 0.0005mm/.00002” linear scales have zero backlash and are mounted in the center of the stage movement for increased accuracy.
• The optics and workstage movements are mounted on cast granite composite base.
• Single hand quick release table allows for rapid travel and fine adjustment.
• The y-axis drive is mounted directly under the center of gravity for better weight distribution and increased accuracy. The handles are located for operator comfort during use.
• True par focal helix adjustment +/- 15 degrees with 5 minute vernier.

For more information please visit 16H Optical Comparator page at Dorsey Metrology website.

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With the use of computers, Pi has been calculated to over 1 trillion digits past the decimal. Pi is an irrational and transcendental number meaning it will continue infinitely without repeating. The symbol for pi was first used in 1706 by William Jones, but was popular after it was adopted by the Swiss mathematician Leonhard Euler in 1737.

π is an irrational number, which means that its value cannot be expressed exactly as a fraction m/n, where m and n are integers. Consequently, its decimal representation never ends or repeats. It is also a transcendental number, which implies, among other things, that no finite sequence of algebraic operations on integers (powers, roots, sums, etc.) can be equal to its value; proving this was a late achievement in mathematical history and a significant result of 19th century German mathematics. Throughout the history of mathematics, there has been much effort to determine π more accurately and to understand its nature; fascination with the number has even carried over into non-mathematical culture.

A Brief History of Pi

Ancient civilizations knew that there was a fixed ratio of circumference to diameter that was approximately equal to three. The Greeks refined the process and Archimedes is credited with the first theoretical calculation of Pi.

In 1761 Lambert proved that Pi was irrational, that is, that it can’t be written as a ratio of integer numbers.

In 1882 Lindeman proved that Pi was transcendental, that is, that Pi is not the root of any algebraic equation with rational coefficients. This discovery proved that you can’t “square a circle”, which was a problem that occupied many mathematicians up to that time.

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Dorsey Metrology, one of the world’s most respected gage makers manufacturing optical comparators in the US, is proud to announce the latest addition to their expanding range of products.  This new comparator has the same high quality features as the current product line, but in a smaller package and at a lower price point.

The New 14″ Industry Standard The 14HE has a 14 inch/350 mm diameter screen and an 8″ x 4′ X andY travel.  The nickel plated cast iron work-stage has both coarse and fine adjustment control together with a massive 50lb working capacity.  As always, cross roller bearings are on all three axes.  Dorsey is known for their unique internal edge detection, which is optional on this model.  A variety of digital readouts from different manufacturers are offered to compliment this. Features:

• 14″ (350mm) screen for optimum viewing
• High resolution ground glass screen with 90 degree cross lines and chart clips
• Machined chart ring with vernier protractor, 1 minute graduation
• Output for electronic rotary screen protractor
• Coated telecentric par focal optics
• Available optional internal edge sensing
• Quick change single lens mount
• Optional Fiber optic surface illumination
• Nickel plated, completely cast iron workstage with single universal dovetail
• Triple axes solid crossed roller stage system
• 16″ x 4″ overall stage size
• 8″ X axis travel with “glide release”
• 4″ Y axis travel (rise & fall)
• 50 lbs. capacity
• ± 5 degree lightsource helix adjustment
• NIST traceable calibration certificate
• 2 year limited warranty

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We are getting ready to start producing video podcasts too. Keep your fingers crossed.

In the meantime we will try to keep this blog constantly updated with more information about optical comparators.

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I’ve been using linux distributions for 11 years now and I saw a lot of changes. Perhaps too many. From solid rock server system developers took different approach to make it more user friendly. And I agree with that, but that famous Unix simplicity has disappeared somewhere along the road. Linux systems became more user friendly, thus more available for ordinary users.

However, developers aiming at wider user base introduced new challenges for old school sysadmins and geeks. These days I hardly see Windows or Mac system crash, Linux starts to remind me of Windows 98. I don’t get blue screens but hard crashes occur quite often. Probably the problems behind it are faulty device drivers. Linux community did a fantastic job making that system work on various hardware configurations, but it’s still far from perfect.

However, it’s all community driven. Linux needs powerful company behind it. Linux needs someone that can influence hardware and software makers to release their products with Linux support. Linux needs company that can provide enterprise class support. And Linux needs a company with worldwide marketing capabilities. Without it it will never shine on desktops. It needs a push in corporate market. And without powerful company support it doesn’t stand a chance.

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Dial test indicator shown above is Dorsey Metrology model TI4-005D. Indicator can be purchased as a standalone dial test indicator or as a kit with additional contacts. For more information visit Dorsey’s dial test indicator page.

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14HE optical comparator made by Dorsey Metrology.

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When ordering optical comparator chart, please specify the following:

• style of chart (more available – images coming soon)
• type and model of optical comparator
• lens magnification
• chart material – glass or plastic
• additional information required for particular chart or scale

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