The book! The gage block thing you talked about reminded me (a bit) of how you test a clock (for stability). One way is to build three clocks and then test each one against the other two. That way you can find the most stable.
Say, I downloaded the pdf version is this djvu format much better? George H.
That Book/Archive item is too new to the Archive. They stopped creating djvu versions a little over a year ago. So not to worry, there is no djvu version to download :(
Curious to know if the original scan material is better. I've mucked through some smaller sets of raw data before. You will probably find skewed pages and a few other warts. They show it was scanned at
300dpi. The better looking docs are usually done at 500dpi. Post a little follow up about what you found if you get a chance :)
I don't think the djvu format is available for this file.
I downloaded the 331 Mb JP2.ZIP file and opened up some pages in Adobe Photoshop CC. They look the same as the PDF. In other words, the problem was in the way images were handled in the original scan.
The JP2s have much higher resolution -- you can see the screen dots in the photos as sharp as a tack -- but it doesn't help. It's not a matter of resolution. It's the way the grayscale threshholds were set.
So, enjoy the book. You can see enough with the photos in the PDF. You're just missing the gorgeous, creamy tones in the original B&W photos.
It is a fantastic book. Moore Special Tool Co., like this book, was a national treasure. I spent a lot of time up there when I was a writer for _American Machinist_.
I looked at the JP2 images and they look the same as the PDF. It was in the scanning, probably in the way the grayscale threshholds were set. They look like photostats.
Well I'm a hack when it comes to machining. But I look forward to reading the book. I'm mostly a physicist by training. Let me offer "Instruments and Experiences" by RV Jones as one of my favorite books with many mechanical insights.
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There is some optical stuff that you may not like, but it has lots of good mechanical/ instrument ideas and some fun stories. (The Felling of a chimney... I went looking for this on the web, no luck. if there's interest I'll scan some and post)
The bad news is that this book is hard to find. I spent ~$100 for a used copy from India several years ago.
Thanks. I was hopeful but not surprised. I've done some trial & error work with scanning and document creation. It isn't a straight forward process. A lot of the good old material at Archive was done with a Canon 5D camera and 500dpi. You could see the focus shift (fuzzy) as the pages were turned and thickness changed sometimes. I guessing but the operator needed to adjust the focus distance more often...
I can make djvu docs but not of the quality they have. Lizard Tech used to be the djvu vendor:
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It broke my heart when Archive dropped making djvu docs :(
I haven't done any camera copy work for a while, but I have a 24 Mp camera (Sony NEX-7) and some flat-field lenses for it, including a Micro Nikkor and a Schneider Componon on a bellows. I'll give it a try one of these days.
Gee, you have all kinds of interesting interests. If you like that stuff, I should mention that I also have Zeiss and Schneider process lenses for my view camera -- extreme flat-field lenses used in photoprocess and copy work. Before they hired me to write, I did technical photography for McGraw-Hill Publishing Co. I did a lot of off-the-wall technical photo work in those days.
I did silver-masking of 35 mm Kodachromes for them, in my darkroom, charging, IIRC, around $15 each. I ganged them and could do 24 of them in an evening after work, but the jobs only came up from time to time.
Silver masking produces the same result as today's "unsharp masking" filters in Photoshop and Gimp. It was a pretty technical skill. Today, a five-year-old can push a button and do it in five seconds.
Yeah, I use to fix stuff, good thing I retired when I did. Still do for friends when I feel ambitious, which isn't often nowadays. Now people replace stuff, even the "repair" guy...
Hope you enjoy poking around in the old books at Archive :)
Yeah, the new "techs" are board replacers because the computer diagnostics told them to do so.
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A human being should be able to change a diaper, plan an invasion, butcher a hog, conn a ship, design a building, write a sonnet, balance accounts, build a wall, set a bone, comfort the dying, take orders, give orders, cooperate, act alone, solve equations, analyze a new problem, pitch manure, program a computer, cook a tasty meal, fight efficiently, die gallantly. Specialization is for insects.
In 1970 the Army trained me to repair computer communications 'peripherals' to the component level after memorizing the machines' operations, but the material was so difficult that only students with science degrees completed it. Four of us survived the forty week course, whittled down from over 80 entrants. We were available only because the grad school draft deferment had been dropped.
The Army was soon forced to revert to a test procedure for board swappers. I think the problem was that people who could do it were qualified for better jobs. I certainly preferred designing and building new equipment over repairing older stuff.
I was working in the semiconductor industry when surface mount came out. Circuit board layout became much simpler without the forest of vias to dodge, especially for inner signal layers on increasingly dense computer boards. That soon translated into physically smaller but equally challenging designs.
The pads for drilled holes had to be excessively large to avoid misalignment between the photoetched copper and the separately drilled holes. They are drilled in a stack and the glass fibers randomly deflect the tiny bit as it goes deeper. Boards were rejected if there wasn't a minimum ring of copper all around the drill hole, because it wouldn't plate all the way through reliably. The hole is drilled larger than the specified finished size to allow for plating.
It was recognized that surface mount boards may not be repairable but the greatly reduced manufacturing cost balanced out the high price of qualified repair technicians, the overhead of handling returns and the higher potential of subsequent failure on hand-reworked boards.
Typically a small subset of boards caused repeated trouble while the rest worked fine until obsolete. About half the field returns I tested showed no fault on my test system.
I buy, recondition and use older lawn and garden equipment because it's made of metal that I can repair or copy instead of molded plastic I often can't. Yesterday I forged a pair of long canning-type tongs from 1/4" gas welding rod to handle firewood for the stove.
The kitchen tongs I can buy don't last long. Fireplace tongs are intended to grab the middle crosswise rather than the end lengthwise.
I recently repaired a printer for a neighbor -- fixed a mechanical problem with the paper feed deep inside the printer. Neighbor said I should go into business repairing printers. I pointed out that for my time at minimum wage I would have to charge twice what a new printer would cost.
Wow, large drop rate. I learned the basics at Coleman College, but only stayed working in the field for 3 years. That means I don't have a firm background in it, unfortunately, and can't look at a circuit on the PCB and tell you what it does and how. :-( SKS bought the company I worked for and moved it to Sandy Eggo, changing my 11 minute commute to over 2 hours per day. I took the separation package.
Good for you, and I can certainly understand your preference. Who repaired the boards, or did they? That would be good stock to help turn the board swappers into real techs.
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A human being should be able to change a diaper, plan an invasion, butcher a hog, conn a ship, design a building, write a sonnet, balance accounts, build a wall, set a bone, comfort the dying, take orders, give orders, cooperate, act alone, solve equations, analyze a new problem, pitch manure, program a computer, cook a tasty meal, fight efficiently, die gallantly. Specialization is for insects.
AFAIK we were trained to the Depot (highest) level although we didn't have comparable test or soldering equipment, if any, in the "field", more often a forest. In fact during Vietnam Europe was starved of everything, we couldn't even get wiper blades etc for Jeeps and kept about half our allotment of them running with personal purchases from J.C.Whitney, which resulted in dangerously overpowered engines and numerous roll-overs on winding back roads better suited to the Ultimate Driving Machine. Most soldiers didn't go off base and thus had money to burn.
Testing has evolved in the direction of not requiring expert operators, it leverages the knowledge that designed / debugged the prototype.
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The Golden Board test is a good example. It and the Device Under Test are driven identically in parallel and the test station or operator looks for differences. The test station designer (me) needs to provide a black-box imitation of the rest of the system.
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