Stability of Flat Bed Presses.

A flat letterpress machine only operates correctly when the sheet of paper to be printed and the forms cover the same distance during the same time. This may be controlled with the aid of a slipmeter which shows the difference between the two elements. When measuring it is important not to compress the cylinder covering. Differences in the covered distances may be attributed to: 1. Wrong choice of cylinder covering; 2. Wrong dimensions of such parts as cylinder, bed bearers, cylinder bearers and bed; 3. Insufficient pressure between the bed bearers and cylinder bearers; 4. Differences as a result of bending of the cylinder, bed and frame; 5. Inaccurate height of type.