Of course the components would be mm, they are all small items and should be mm. I am talking the layout of these drilled holes (not hole size), studs, columns, or walls for buildings, or slopes, pitches, room sizes, levelness, and areas sizes -- mm precision does not make sense. Cabinetry, is not building construction, needs more precision than a building. What is the tolerances in construction that requires +- 1 mm exactness, that cm or tolerances of +-.25 cm can not be used? A drill is a drill is a drill, it is not hole distance, or board length or layout. Just for reference 1/16" is 1.6 mm rounded. 1/8" is 3.2 mm 1/4" is 6.4 mm, since I am American and was never taught Metric in school. Anyways I did not think 1.1 cm, 2.2 cm, 3.3 cm .... 9.9 cm would be a problem. I guess it does not matter.
Id put my money on the sun and solar energy. What a source of power! I hope we dont have to wait til oil and coal run out before we tackle that. I wish I had a few more years left. -- Thomas Edison♽☯♑ ----- Original Message ----- From: "John M. Steele" <jmsteele9...@sbcglobal.net> To: "U.S. Metric Association" <usma@colostate.edu> Sent: Friday, December 10, 2010 7:40:04 AM GMT -05:00 US/Canada Eastern Subject: [USMA:49117] Re: Construction SI Centimeters might suffice for some measurements. But many fasteners, panel thicknesses, cabinetry thicknesses, drill holes etc would require millimeters. One or the other would have to be labelled on the drawing with units EVERYWHERE. Drawings that have a standard unit unless otherwise noted are MUCH easier to read. By convention, including ANSI SI10 and other standards, that dimension is millimeters, in virtually all industries. (IC chip design would be more likely to use micrometers) Calculators which offer engineering notation (powers of ten which are also powers of 1000) allow convenient substitution of prefixes for the engineering notation, whereas centimeters require you to stop and think every time. Structural calculations would be a nightmare. In construction, the first order of business is that the project shouldn't collapse. If you want "rounder" numbers, just insist most dimensions be a multiple of 10 mm. Problem solved. Anyway, a prefix doesn't create a new unit. It is still the base unit with a prefix substituted for a power of ten in scientific notation. (I think Pat will contest this.) From: "a-bruie...@lycos.com" <a-bruie...@lycos.com> To: U.S. Metric Association <usma@colostate.edu> Sent: Fri, December 10, 2010 6:54:25 AM Subject: [USMA:49114] Construction SI First, is there an archive of this forum? Second, I still do not get why the building industry choose to favor millimeters vs. using centimeters. As a toolmaker, of course, millimeter and micrometer is mostly used in the blueprints but millimeters in construction? When a quarter inch is refereed to most often, as in a slope of 1/4" to 12", in metric would simply be 2 cm to 1 m or 2%. Or using 8.25 cm vs. 82.5 mm for 3 1/4". When building homes and skyscrapers, mm, do not make sense, to me. I do not get their reasoning. Id put my money on the sun and solar energy. What a source of power! I hope we dont have to wait til oil and coal run out before we tackle that. I wish I had a few more years left. -- Thomas Edison♽☯♑
