On 7/31/15, D. Hugh Redelmeier <hugh@mimosa.com> wrote:
On Fri, 31 Jul 2015, Russell Reiter wrote:
<snip>
I think you mean "six sigma".
Umm. Six sigma is a corporate SAP construct. Put forward by Motorola if I recall correctly. A sic sigma table is one written, sic erat scriptum, thus it was written.
Uneducated prejudice:
Six sigma started out as a somewhat arbitrary quality metric. Sigma is the standard deviation of a distribution. Six sigma is meant to be six standard deviations away from the mean. I think that the distribution is assumed to be Gaussian (Bell Curve), which is usually safe, but probably not so far from the centre.
Now six sigma is a religious movement for improving manufacturing and various other business processes.
I don't actually understand your usage.
The rafter tables on my framing square were referred to as sic sigma. It's a set of tables by which oblique and other angles which which are used to join wooden members in a hip and valley roof may be calculated. Roofs and stairs are not calculated by angles as such, but by rise over run as in height over length. If you ever looked at a hip roof dormer before it was skinned over you would see "crippled" members which have an angle cut on the narrow face an angle cut on the wide face which is then cut on an oblique bias. There is a little birds mouth notch so that the member sits level on the top plate of the wall. This can all be calculated from the tables as they are written on the rafter square. All cuts can be made on the ground as well as the calculations to increase the length of the members so they stay 16 or 24 inches on centre as they increase in length to match the oblique angle of valley where the dormer joins the main roof. Sic erat scriptum by R. Russell Reiter this; the day of our Lord; July 31, 2015 etcetera, etcetra etc... There are some parts of the English language I don't miss. I was never very good at latin either. ;-)
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