What is a Honed Tube? Bore Tolerance, Finish and Applications
Honed tube is the standard barrel material for hydraulic cylinders. Honing removes material with abrasive stones in a crosshatch pattern, producing an accurate, round, straight bore with a controlled surface texture that holds a lubricating oil film.
Why bore tolerance matters
Hydraulic piston seals are designed around a specific bore diameter. H7 tolerance keeps the seal compression inside its design window along the entire stroke, so the cylinder neither leaks internally nor drags. A bore that varies along its length wears seals unevenly and causes early failure.
Surface finish and the crosshatch pattern
The crosshatch left by honing retains a thin oil film that lubricates the seal. Too smooth and the film breaks down; too rough and the seal abrades. A typical hydraulic honed tube is supplied in the range of Ra 0.2 to 0.4 microns.
Standard sizes and material
- Common sizes: 40 × 50, 50 × 60, 63 × 76, 80 × 95, 100 × 114, 120 × 140 and 125 × 145 mm.
- Bore range 20 mm to 500 mm, lengths up to 5000 mm.
- Seamless steel supplied to DIN 17175, annealed for machinability.
- Eddy current tested and tensile tested before honing.
How honed tube is produced
Raw seamless tube is inspected, then skived and roller burnished to remove the as-drawn surface and work-harden the bore. Final honing brings the bore to H7 and sets the surface finish. Tubes are then cut to length, cleaned, oiled and capped for transport.
Frequently asked questions
Is honed tube the same as a hydraulic cylinder tube?
In practice yes — honed tube is the finished barrel stock used to build hydraulic cylinders, supplied ready to use with an H7 bore and micro-finished surface.
Can honed tube be cut to length?
Yes. Honed tubes are cut to your required length and deburred, and Pioneer Hydraulics supplies bore sizes from 20 mm to 500 mm in lengths up to 5000 mm.