Hydraulic piston seals depend on the gland geometry around the seal, the operating pressure, the extrusion gap and the selected backup-ring arrangement. Parker’s O-Ring Handbook lists basic groove dimensions for specific dynamic piston-seal configurations. This table reproduces selected metric O-ring sizes and associated dimensions from that handbook table.

Each row keeps Parker’s O-ring number and dimensional symbols. The d1 and d2 values describe O-ring inside diameter and cross-section. The b1, b2 and b3 values correspond to the handbook’s groove-width options for zero, one or two anti-extrusion rings. The remaining diameter labels, d4/d9 and d3, are preserved as shown by Parker; use the handbook drawings and notes to interpret their exact geometry and tolerances.

Choose the row and arrangement carefully

Begin with the exact O-ring number or dimensions required by the seal design. Then identify whether the piston arrangement uses no backup ring, one ring or two rings. Do not select a groove width only by matching the O-ring cross-section. The groove arrangement, backup-ring geometry and handbook tolerances all matter.

The listed dimensions are for the handbook’s dynamic hydraulic piston application. They do not represent every metric O-ring standard, every elastomer, or every piston seal profile. These rows are not rod-gland dimensions. Do not transfer the values to a static face seal, pneumatic seal or custom groove without checking the governing design guidance.

Check the operating conditions

Pressure and clearance influence extrusion risk. Also consider the fluid, temperature range, compound, hardness, surface finish, motion speed, stroke, lubrication and assembly method. A groove that matches a nominal size can still fail if the extrusion gap is too large or the material swells in the fluid. A backup ring can alter installation and groove-width requirements.

Review the handbook’s complete tolerances and assembly drawings before machining. Verify the actual piston and bore dimensions, concentricity, edge breaks and surface finish. Sharp edges can damage an O-ring during installation, while an incorrect gland depth can cause underfill or excessive squeeze. Follow the seal supplier’s current guidance for the chosen compound and duty cycle.

On a drawing review, check that the selected b1, b2 or b3 width matches the specified number of backup rings and that the drawing uses the same Parker table and application. Then inspect the complete tolerance stack, not just nominal dimensions. A nominally correct groove may still produce too much squeeze or too little support at a tolerance limit. Confirm assembly clearance and the supplier’s installation guidance before releasing the piston for manufacture.

Use the handbook as the controlling reference

The table is a compact lookup aid for the selected Parker sizes. It intentionally retains the source nomenclature so that a designer can cross-check each entry against Parker’s Table 3.13 and its accompanying diagrams. If a drawing, customer specification or current handbook revision differs, resolve that discrepancy before manufacturing.

These basic dimensions do not by themselves verify pressure capacity, leakage performance, friction, wear life or fluid compatibility. Use them as one part of the seal design, followed by review of the actual gland, operating envelope and applicable engineering requirements.

The values are from Parker Hannifin’s O-Ring Handbook PTD5705-EN, Table 3.13, for selected metric dynamic hydraulic piston-seal groove sizes. Consult the handbook table and drawings for the full context and tolerances.

A useful cross-check is the 2-014 entry: Parker lists a 12.42 mm inside diameter, a 1.78 mm cross-section, and groove-width options of 2.8, 4.2 and 5.6 mm. The corresponding b1, b2 and b3 values follow the zero, one and two backup-ring arrangement headings. This example is a table readback, not a complete gland design.

Do not confuse these values with pneumatic piston grooves, rod-seal glands or other O-ring groove tables in the same handbook. The table number and application caption matter as much as the nominal O-ring dimensions.