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Metalworking (rec.crafts.metalworking) Discuss various aspects of working with metal, such as machining, welding, metal joining, screwing, casting, hardening/tempering, blacksmithing/forging, spinning and hammer work, sheet metal work. |
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Starret Mics....6-18" (12 of them)
"DoN. Nichols" wrote:
On 2010-08-04, Gunner Asch wrote: http://inlandempire.craigslist.org/tls/1873615296.html Hmm ... no mention of the standards, and the one opened box shown does not have the standards present. For that price, I would expect the standards, too. What do you think your chances are of measuring something 17.75" to 0.0001"? No standards would indeed be a deal killer. Wes -- "Additionally as a security officer, I carry a gun to protect government officials but my life isn't worth protecting at home in their eyes." Dick Anthony Heller |
#2
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Starret Mics....6-18" (12 of them)
On 2010-08-07, Wes wrote:
"DoN. Nichols" wrote: On 2010-08-04, Gunner Asch wrote: http://inlandempire.craigslist.org/tls/1873615296.html Hmm ... no mention of the standards, and the one opened box shown does not have the standards present. For that price, I would expect the standards, too. What do you think your chances are of measuring something 17.75" to 0.0001"? *With* standards -- and in a temperature controlled room with good thermally insulating gloves for handling the micrometer and the standard -- maybe. Let's see -- steel is 11 to 13 E-6 per degree Celsius. So 17.75" would vary 0.000195" to 0.000231" (depending on alloy) per degree C, or 0.000108" to 0.000128" per degree F, so the room would have to be very well temperature controlled, and the parts, micrometer, and standard allowed to "soak" at temperature for quite a while, given the possible mas of a 17.75" part. I think that with that degree of sensitivity, even the person performing the measurement would have to be in a thermally insulated suit -- and perhaps to breathe through a hose to the outside to minimize the effect of his/her breath on the measurement. No standards would indeed be a deal killer. Certainly for me at that price. If the whole set were going for say $200-$300 -- I might consider buying standards as I needed them, and typically one standard for two adjacent size micrometers. (Hmm ... probably a cheap Chinese set of gauge blocks or several (let's see, 6", 3", 2", 1" in the sets, that is 12" -- so two sets might do it.) Enjoy, DoN. -- Remove oil spill source from e-mail Email: | Voice (all times): (703) 938-4564 (too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html --- Black Holes are where God is dividing by zero --- |
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