8 Mar
2013
8 Mar
'13
1:24 p.m.
Fred, you stretched my head when you said helix vs.
spiral. do you get
a helix on a flat plane with just lines on it? I thought helix would be
cylinder ruled with a line. maybe I'm taking what you meant out of
It is.
Helical slide rules, like the Otis King are cuylindrical with the scale
forming a helix around the cylcider (like a screw thread). In the cae of
the Otis King there are 2 cylders with scales that sldie one within the
other and also rotate relative to each other and a cydindrical cursor
that sldis and rotatesa over the outside with an indicaotr lien at eack end.
To do multiplication, you set the line on the cursor agains the '1' on
the lower scale and sldie//rotate the upper scale to align the line at
that end of the cursor agaisn the first number on that scale. Then,
keeping the 2 scales fixed realtive to each other, you move the cursor so
that the bottom line is against the second number on the lower scale. The
upper line then indicates the product o nthe upper scale.
-tony