JDB family · Drawing and duty review required
Mingxin JDB cylindrical oilless bushing
The official JDB sheet describes a brass bushing with embedded graphite lubricant. It identifies F7 bore, m6 outside diameter and an H7 housing recommendation, with size-specific lengths. Load, speed, temperature and service life are not given on that sheet.
Identify the metal matrix and embedded lubricant
The product is labelled JDB cylindrical oilless bushing. Its sheet names CuZn25Al5Mn3Fe3 with graphite lubricant and illustrates discrete dark plugs in the metal body. [1] [2] Ask the quotation to identify the actual offered grade and lubricant; a photograph cannot certify composition, plug quality or wear performance.
The sheet includes a generic bearing drawing and dimensional options, rather than a single complete ordering model. Keep the material, bore, outside diameter, length, tolerance basis and document revision together when specifying an order.
A dot means a listed combination, not current stock
| Bore d | Outside diameter D | Lengths L marked in the reviewed row |
|---|---|---|
| 20 | 28 | 15, 16, 20, 25, 30, 35, 40, 50 |
| 20 | 30 | 12, 15, 16, 20, 25, 30, 35, 40, 50 |
| 30 | 38 | 12, 15, 16, 20, 25, 30, 35, 40, 50, 60 |
| 30 | 40 | 12, 15, 16, 20, 25, 30, 35, 40, 50, 60 |
| 50 | 60 | 30, 35, 40, 50, 60, 70, 80 |
These are five selected rows, not the entire catalogue or an availability feed. [2] Read across the exact d/D row to a dotted L column. The blank cells do not establish that a custom size is impossible; ask for a controlled offer. The drawing labels length limits of −0.10 / −0.30 mm; reconfirm their application to the selected item and revision.
The matrix lists both 20 × 28 × 25 and 20 × 30 × 25 mm. Their outside diameters differ by 2 mm; calculated nominal wall thicknesses are 4 and 5 mm respectively, using (D − d) / 2. This arithmetic does not establish installed clearance, load capacity or interchangeability. A “20 × 25 bush” description is incomplete.
The sheet gives recommendations, not one universal shaft fit
| Item | Published notation | What must be confirmed |
|---|---|---|
| Bushing bore d | F7 | Selected size’s numeric deviation and whether the dimension applies before or after installation |
| Bushing outside diameter D | m6 | Selected drawing, housing material and intended retention/installation |
| Housing | H7 recommended | Actual bore condition and assembly requirements |
| Mating shaft | d8: high load; e7: light load; f7: high precision | Which recommendation applies to the defined duty and what resulting clearance is approved |
The notes are supplier recommendations reproduced from this sheet. [2] Do not treat the uppercase bore F7 and lowercase shaft f7 as the same tolerance. Ask for the actual mating drawing and approved installation process. The catalogue diagram cannot account for a worn pin, distorted housing or a temperature-dependent installed condition.
Dimensions do not answer the operating-duty question
Describe the duty
Load direction and peaks, movement type/range/frequency, shaft and housing materials, surface condition, temperature, contamination and lubrication/maintenance provisions.
Request the material-specific evidence
Applicable load, speed and combined duty limits, installation/running-in instructions, wear acceptance and supporting test conditions for the selected configuration.
The JDB sheet supplies no load, speed, PV, temperature or life rating. Its separate 2018 excavator article ends with a different company’s name and contains corrupted units. [3] Those figures are not imported into this page or structured data. “Self-lubricating” is not a machine-life guarantee or permission to neglect contamination and pin condition.
How should a first sample be accepted?
Approve the drawing and material first, then agree the dimensions and condition to inspect, including the installation stage at which clearance is evaluated. Identify the delivered sample or lot and distinguish dimensional acceptance from a representative wear test or a machine-specific validation. CivilEquip has not performed any of those tests.
Request a complete JDB drawing and duty review
Sources & review
- Mingxin official JDB product ↗
Family identification and manufacturer product photograph. Detail is an embedded illustrated sheet.
2026-10-11 - Official JDB sheet · printed page 13 ↗
Material, fit drawing and dotted bore/outside-diameter/length matrix, visually reviewed. No pressure, speed, PV or temperature rating in this sheet.
2026-10-11 - 2018 excavator article · excluded performance evidence ↗
Different company named at the end and corrupted load units. Figures are not attributed to this JDB family.
2026-10-11
Specifications come from the manufacturer’s published information and the sources above; buying advice is written by CivilEquip with AI assistance. Ask the manufacturer to confirm the data for your configuration. Editorial policy · Report a correction.