When selecting a custom hydraulic cylinder supplier, ask how the company turns an operating requirement into a reviewed drawing, a manufactured product and an inspection record. A quotation alone cannot show whether the proposed cylinder fits the machine or how the final unit will be verified.
Start with engineering review
Share the application, load cases, pressure, stroke, mounting geometry, speed, duty cycle, fluid and environment. Ask the supplier to identify missing inputs, side-load risks, rod stability questions and interfaces that require confirmation. Record who approves the final drawing and how revisions are controlled.
Check manufacturing scope
Clarify which operations are performed in-house and which are subcontracted: machining, welding, heat treatment, surface protection, assembly and testing. For critical parts, agree on material specifications, traceability and applicable welding or coating procedures. Ask for a manufacturing plan aligned with the project requirements rather than a generic capability list.
Request a project inspection plan
The inspection plan should name dimensions and tolerances to be checked, pressure and leakage test methods, movement or cushioning checks, and any customer witness points. Test pressures and pass criteria must match the approved design and applicable standard. Ask how nonconformities are documented and resolved.
Review documents and after-sales support
Depending on the project, the handover package may include approved drawings, material certificates, weld and coating records, dimensional reports, test results, operating instructions and preservation details. Confirm spare seal information, identification marking and support for installation or commissioning before purchase.
Compare like with like
When comparing quotations, check the same scope for materials, mounting hardware, sensors, coatings, tests, documentation, packaging and delivery terms. A lower initial price may reflect a smaller scope. Ask each supplier to state exclusions and assumptions explicitly.
Yongjian’s company page describes engineering, machining, welding, assembly, coating and hydraulic testing capabilities. Its crane cylinder page explains drawing-based customization and project-specific confirmation. Use these as starting points, then send your drawings and inspection requirements to request a specific proposal.