The C-Channel Bolster construction uses "C" channel on both the upper and lower bolsters. The channel runs the length of the bolsters with cross braces of channel used as structural support.

• Threaded rod assemblies connect the upper and lower bolsters.
  
• This connection provides a "fixed daylight" (vertical distance between the platen base and upper bolster). Fixed daylight requires that all tooling used must be the same thickness. The daylight can be increased or decreased, but requires manually adjusting all the threaded rod assemblies independently to raise or lower the upper bolster. This process can take several labor hours each time it is performed.
  
• Advantages:
  
  • Lower cost than Welded Bolster Construction
    
• Disadvantages:
  
  • Manually Adjustable Daylight only
    Cannot be ground or machined to tight tolerances.
    Tolerances:
    
    • Flatness, +/- .50 mm maximum
      
    • Deflection, .75-1.0 mm across typical C-channel press widths (1000 mm)
      
• Because of lower tolerances, C-channel construction is primarily for the industrial, recreational and lower tolerance aerospace production applications.