Dimensions of Steel Cylinders.
All dimensions in inches.


 ##       DIAMETER         LENGTH        CIRCUMF
------------------------------------------------
  A          3.000         39.924          9.425
  B          4.854         24.674         15.250
  C          7.854         15.250         24.674
  D         12.708          9.425         39.924
  E         20.562          5.825         64.598



*  Cylinder "A" is a length of 3 inch OD steel tubing, with wall thickness 0.065 inch.  (as close as possible to 0.0625).  For example, McMaster Carr part no. 3094K53

*  Cylinders are made of 16 gauge mild steel, which is 1/16 inch thick (0.0625).

*  Cut out rectangles of material from a 4x8 sheet of steel.  Roll them up on a sheet metal roller, and Seam Weld the ends together.  In a Seam Weld, the ends of the material butt up against each other -- they do not lap over each other. 

*  TIG weld with Argon.

*  All cylinders have equal mass and surface area.

*  Relative Magnetic Permeability (mu) of steel = 100 to 180