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ISO 28927-5:2009 — Hand-held portable tools — Vibration test for drills and impact drills
Laboratory measurement of hand-transmitted vibration for drilling tools | Engineering technical guide
Introduction to ISO 28927-5
ISO 28927-5:2009 specifies a laboratory method for measuring hand-transmitted vibration emission at the handles of hand-held power-driven drills and impact drills. It replaces ISO 8662-6:1994, now covering non-impacting drills in addition to impact drills. The standard applies to straight drills, pistol-grip drills, and angle drills driven pneumatically, hydraulically, or electrically.
This standard uses different test methods for drills with and without impact action: non-impact drills are tested drilling into grey cast iron or mild steel, while impact drills are tested drilling into a standardized concrete block.
Key Technical Requirements
Test Conditions by Drill Type
For drills without impact action, the test method depends on rotational speed. High-speed drills (≥10,000 r/min) are tested running free with a 1.5 mm drill bit since the unbalance contribution dominates. Lower-speed drills drill into grade 250 grey cast iron or E235 mild steel with specified feed forces.
| Speed (r/min) | Method | Drill Bit | Feed Force (N) |
|---|---|---|---|
| ≥ 10,000 | Free running | 1.5 mm | 0 |
| 5,500-10,000 | Drilling grey iron | 1.5 mm | 0 |
| 3,100-5,499 | Drilling grey iron | 3 mm | 50 |
| 1,000-3,099 | Drilling grey iron | 6 mm | 100 |
| < 1,000 | Drilling grey iron | 10 mm | 150-200 |
Impact drills use an 8 mm drill bit drilling into a concrete block (min 500 x 500 x 200 mm) with compressive strength ≥ 40 MPa. Feed force is 150 ± 30 N in addition to drill mass.
Engineering Design Insights
The concrete formulation for impact drill testing is precisely specified: 450 kg cement, 0.22 m³ water (water/cement ratio 0.49 ± 0.02), and 1,450 kg aggregate with controlled particle size distribution. Very hard aggregates (flint, granite) and very soft aggregates (limestone) are explicitly prohibited to ensure consistent drilling resistance.
For non-impact drills, the test measures drilling through 20 mm thick plates. Each test series consists of five holes drilled, with measurements starting when the bit contacts the plate and stopping after 8 seconds or when the hole is completed.
The standard strongly recommends mechanical filters for impact drill measurements to prevent high-frequency shock pulses from saturating the measurement system.
Vibration Declaration
Three operators each drill five holes. The coefficient of variation Cv must not exceed 0.15, and standard deviation sn-1 must not exceed 0.3 m/s², or the data must be checked for errors.
Frequently Asked Questions
Q: Why do high-speed drills use free-running tests?
A: At speeds ≥ 10,000 r/min, the unbalance of rotating parts dominates vibration, making the drilling process contribution relatively insignificant.
A: At speeds ≥ 10,000 r/min, the unbalance of rotating parts dominates vibration, making the drilling process contribution relatively insignificant.
Q: What concrete specification is used for impact drill testing?
A: Non-reinforced concrete with 40 MPa compressive strength after 28 days, with specific aggregate particle size distribution.
A: Non-reinforced concrete with 40 MPa compressive strength after 28 days, with specific aggregate particle size distribution.
Q: How is feed force measured during testing?
A: The operator stands on a scale during drilling, providing real-time feed force monitoring with accuracy better than 1 N.
A: The operator stands on a scale during drilling, providing real-time feed force monitoring with accuracy better than 1 N.
