Dancer Cylinder Pressure Calculator

Estimate the cylinder pressure needed to balance a target web tension through a measured dancer-arm geometry.

Target web tension (N)Total tension in one web span.Loaded web spansA 180° wrap normally loads the dancer through two spans.Pivot to dancer roller (mm)Measure perpendicular effective lever distance.Pivot to cylinder connection (mm)Use the effective lever distance at the calculation position.Cylinder bore (mm)Use manufacturer bore, not outside body diameter.Rod diameter (mm)Enter 0 for the cap end; enter rod diameter for annular area.Number of cylindersParallel cylinders share required force through total area.

Enter tension, geometry and cylinder dimensions.

What this calculator solves

A dancer pressure gauge is not a direct tension reading. Web spans load the roller, the arm changes that force through leverage, and cylinder area converts required force into pneumatic pressure.

Inputs and units

Use total newtons per span, whole loaded-span and cylinder counts, effective arm distances and the active piston diameter. If pressure acts on the rod side, subtract rod area by entering its diameter.

Calculation method

Roller load = tension × loaded spans. Cylinder force = roller load × roller arm ÷ cylinder arm. Pressure = cylinder force ÷ total active piston area.

Worked production example

Two spans at 100 N load a dancer with 200 N. A 400 mm roller arm and 200 mm cylinder arm require 400 N. One 50 mm cap-end cylinder therefore needs about 203.7 kPa, 2.04 bar or 29.5 psi.

How to use the result

Use the nominal value as a commissioning cross-check, then compare it with measured load-cell tension through the full dancer travel. Record arm position because changing angle changes effective leverage.

Common production mistakes

Do not divide by two automatically; enter the actual number of loaded spans. Do not ignore rod area on retraction, count two cylinders as one, or measure arm length without considering the force direction.

Assumptions and limitations

The calculation assumes static planar leverage. Dancer weight, counterbalance, seal friction, changing angle, acceleration, regulator droop and bearing friction are excluded and may be material in a real machine.

Related workflow and sources

Warner Electric and TJ Walker document the same span, lever and cylinder-force relationships. Continue with Web Tension Force. Warner Electric tension-control guide. Last reviewed: 2026-08-27.