Originally posted by Bented
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Jo Blocks Maintenance Question
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An oldtimer gave me a tip that may be useful at this time, regarding use and temporary storage during hot weather. After usage, when putting them away, wipe them down with silicone cloth. I sometimes use a paper towel soaked with spray silicon.
Sarge41
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Originally posted by dian View Postremove burrs? from hardened precision blocks?...
Don't just take my word for it. See what Starret / Webber says: Stoning Gage Blocks
Best Regards,
BobLast edited by rjs44032; 04-15-2021, 03:08 PM.
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Anything more tham a gentle rub with an oily cloth risks more than the staining being left alone. You should the set we have at the museum, I scraped the rust off with a Stanley knife blade, they will never wring together, but they are all we have got and using up to three together has no measurable loss using a tenths micrometer.
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Checking the blocks with a tenths mike seems a bit backwards. I guess a case could be made by saying that it provides a rough check of the blocks and if they pass that then they are probably OK to check the (same) micrometer with.
Perhaps someone here can donate an old set.
Originally posted by old mart View PostAnything more tham a gentle rub with an oily cloth risks more than the staining being left alone. You should the set we have at the museum, I scraped the rust off with a Stanley knife blade, they will never wring together, but they are all we have got and using up to three together has no measurable loss using a tenths micrometer.Paul A.
SE Texas
And if you look REAL close at an analog signal,
You will find that it has discrete steps.
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Originally posted by Paul Alciatore View PostChecking the blocks with a tenths mike seems a bit backwards. I guess a case could be made by saying that it provides a rough check of the blocks and if they pass that then they are probably OK to check the (same) micrometer with.
Perhaps someone here can donate an old set.
Just what do you, or any of us, or most commercial shops, have, that would need closer measurement than tenths. And even if you DO have some such thing, do you have the proper temperature controlled room and correct procedures to do the measurements with any semblance of accuracy?
Smaller errors "can" come into play when stacking blocks. Two blocks have twice the "possible" error range of a single block, although the "probable" error is much less.CNC machines only go through the motions
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Gage block clean, recondition, testing, certification: https://youtu.be/mKzFXJCryrU?t=777
If you want the history of the Johannson Co., start at the beginning.
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A list of gauge block refences (some given previously) from the "Knowlege Bases" favorite threads
NIST Gauge Block Handbook:
http://emtoolbox.nist.gov/Publicatio...nograph180.pdf
Federal Specification GGG-G-15C for Gage Blocks and Accessories:
http://www.everyspec.com/FED_SPECS/G/GGG-G-15C_16693/
Starrett recommendations for gauge block use and care:
http://www.starrett.com/docs/other-d...age-blocks.pdf
Mitutoyo Operation Manual for Gauge Blocks
http://www.mitutoyo.co.jp/eng/suppor...uge_Blocks.pdf
Mitutoyo History of Gauge Blocks:
http://www.mitutoyo.com/wp-content/u...Gage-Block.pdf
Early (1907/08) discussion of gauge blocks in "Accurate Tool Work" by Goodrich and Stanley, pp 183-201:
http://books.google.com/books?id=new_AQAAMAAJ&pg=PA183
http://books.google.com/books?id=new_AQAAMAAJ&pg=PA195
Prof. Hugh Jack on gauge blocks:
http://engineeronadisk.com/V3/engine...l#pgfId-141526
Popular Science (1942) on the manufacture of gauge blocks:
http://books.google.com/books?id=2SYDAAAAMBAJ&pg=PA108
Precision Measuring and Gaging (at HNSA)
http://archive.hnsa.org/doc/pdf/precision-measuring.pdf
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There are often facets of gauge block use that people ignore.
Ambient temperature is one such variable, many home shop metrology labs lack climate control.
Almost no home shops or commercial machine shops have the equipment to measure gauge blocks, how do you know that a .1009" block is accurate? It may be .10089"
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And, having the part and the blocks the same temp....... Many labs use a big chunk of metal on which the blocks and part are placed to come to equilibrium in temperature before doing the measurement. Then there is cleaning the blocks and part, handling so as not to disturb the temperature etc.
Luckily, since most home and commercial shops lack the means to measure down to the limits of gauge blocks, these things are less important. Repeatability to a couple tenths is about the best most any ordinary shop can even hope for. Yes, you CAN do better, but it gets maybe 50-100x harder with every decimal placeCNC machines only go through the motions
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Originally posted by J Tiers View PostYes, you CAN do better, but it gets maybe 50-100x harder with every decimal place25 miles north of Buffalo NY, USA
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