Pistons & Glands
Turned pistons, gland bushes and end caps with seal grooves machined to the seal manufacturer’s published housing dimensions.
Seal housings are the whole job
A piston or gland is a simple turned part with one difficult requirement: the seal groove has to match the seal maker’s published housing dimensions, including the groove corner radii and the surface finish of the groove flanks, or the seal will extrude or nibble.
Name the seal manufacturer and series on the drawing. If the seal is open, tell us the pressure, the rod or bore speed, the fluid and the temperature range, and we will quote against a named seal series rather than guess.
Specification
| FIELD | UNIT | ORISE VALUE |
|---|---|---|
| Piston outside diameter range | mm | 40 to 400 |
| Gland bore range | mm | 20 to 260 |
| Diameter tolerance | ISO class | h8 standard · h7 and f7 to order |
| Repeatable diameter tolerance | mm | ±0.02 up to Ø120 · ±0.035 from Ø120 to Ø300 |
| Groove dimensional tolerance | mm | To the seal maker’s published housing table, typically ±0.05 on width and diameter |
| Groove flank roughness Ra | µm | 1.6 maximum |
| Bore roughness Ra | µm | 0.4 maximum |
| Concentricity, seal groove to bore | mm TIR | 0.05 when machined in one set-up |
| Materials | — | 45# / C45E · 40Cr · 42CrMo · Q345B · ductile iron · bronze bushing seats |
| Wear ring seat | — | Machined in the same set-up as the seal groove |
| Surface treatment | — | Phosphate, zinc plating, black oxide or none |
Cushioning. Cushion spears and bushes need tighter concentricity than the rest of the part. If the drawing calls for cushioning, mark which diameters are cushion features so they are machined in the correct order.
Set-up count matters. Where the drawing allows, we machine the seal groove, the wear-ring seat and the bore in a single set-up. It costs nothing extra and removes the largest source of concentricity error.
What we need on the drawing
- Seal manufacturer and series, or the duty conditions if the seal is open
- Groove dimensions with tolerances, including corner radii
- Bore or outside diameter tolerance and its measurement datum
- Thread form and class for rod attachment, and locking method
- Port, bleed and cushion features with their tolerances
- Required concentricity and perpendicularity between features
Send the drawing
Quotation within 48 hours of a complete drawing package.