There is a plan for a self built rolling mill in the book: The
Giant Book of Metalworking Projects
ISBN 0-8306-1357-9 paperback
Published in 1983 by Tab books now out of print
This is a short piece with parts drawings on a very sturdy
simple mill with 3" wide rolls 3 7/8" Diameter.
This book is a collection of shop projects from an industrial
arts educational magazine for shop teachers I believe.
The Mill looks buildable, but I believe that It would cost more
not counting labor than one of the currently advertised cheap
ones in lapidary journal. My Mexican mill cost only about $120 but
I haven’t seen these in the states.
If reworking flat rolls I would advise that you get in touch
with a shop that does hard chrome resurfacing of industrial pump
shafts and compressor rods. This type shop can do perfect work
and the cost may be reasonable. My industrial experience was good
and the prices on much larger work was very reasonable. Jesse