Floor-type cluster mill, preferably with direct hydraulic adjustment

In a floor-type cluster mill for working a high strength material, said mill including a frame, an upper set of rolls rotatably mounted relative to said frame, one roll of said upper set of rolls being an upper working roll, a lower set of rolls rotatably mounted relative to said frame, one roll of said lower set of rolls being a lower working roll mounted in spaced relationship to said upper working roll, the space between said upper working roll and lower working roll being in a path for passage of said material, each roll of said upper set engaging another roll of said upper set, and each roll of said lower set engaging another roll of said lower set,

• the improvement further comprising a first changeable subset of rolls removably mountable with respect to said frame, and a second changeable subset of rolls removably mountable with respect to said frame, at least one of said upper set and lower set comprising a permanent subset of rolls rotatably mounted with respect to said frame, and alternatively, either said first changeable subset of rolls or said second changeable subset of rolls,
• said changeable subset having a first number of rolls including a working roll with a first diameter, said second changeable subset having a second number of rolls less than the first number of rolls, and including a working roll with a second diameter greater than said first diameter.