Property Class 12.9 Steel Five-Lobe Bottom Service Screws for Mobile Devices are supplied to ISO 898-1 property class 12.9. Corrosion behaviour is requires plating or black-oxide protection, the material is magnetic, and the usable service range is commonly limited to approx. +300 °C; confirm against the coating and the load. In practice this grade is the highest common strength class, for high-load machine assembly.
- Grade
- ISO 898-1 property class 12.9
- Corrosion resistance
- Requires plating or black-oxide protection
- Magnetic response
- Magnetic
- Service temperature
- commonly limited to approx. +300 °C; confirm against the coating and the load
Property values are typical for the grade. Certified mechanical test data is available on request for production orders.
Property Class 12.9 Steel Five-Lobe Bottom Service Screws for Mobile Devices are supplied to our own published dimensions — this is a trade-series article rather than one covered by a dimensional standard, so confirm the figures against the part you are replacing. The grade provides requires plating or black-oxide protection and is magnetic; the practical service range is commonly limited to approx. +300 °C; confirm against the coating and the load.
Why Choose Property Class 12.9 Steel for Five-Lobe Bottom Service Screws for Mobile Devices
The highest common strength class, for high-load machine assembly. For five-lobe bottom service screws for mobile devices, this matters when requires plating or black-oxide protection is the primary requirement.
Mechanical & Physical Properties
| Grade designation | ISO 898-1 property class 12.9 |
|---|
| Magnetic response | Magnetic |
|---|
| Service temperature | commonly limited to approx. +300 °C; confirm against the coating and the load |
|---|
| Corrosion characteristic | Requires plating or black-oxide protection |
|---|
Galvanic & Galling Considerations
For five-lobe bottom service screws for mobile devices in steel, the dominant compatibility issue is hydrogen embrittlement at high property classes (10.9 and above) when electroplated. Plating must be followed by an appropriate baking treatment, or a non-electroplated finish (mechanical zinc, zinc flake) should be substituted.
Comparable Grades
For Five-Lobe Bottom Service Screws for Mobile Devices, class 8.8 is the comparable strength step. Move up when the joint preload approaches the proof load of the current class; move down when the joint is over-specified. For corrosion-critical service, switch to stainless A2 or A4.
Sizes of Five-Lobe Bottom Service Screws for Mobile Devices Available in Property Class 12.9 Steel
| Service position | Drive | Driver size (mm) | Typical length (mm) | Length reference | Use |
|---|
| bottom-edge pair | five-lobe | 0.8 | 6.75~6.8 | under head | device-specific replacement part |
Dimensions are independent of the material: every size above is available in Property Class 12.9 Steel.
Custom manufacturing · Made to drawing
Need this screw in a grade that is not listed?
Grade 12 9 Steel is one of the grades the catalog describes. Thread size and pitch, length, property class, drive form, head geometry and head marking are all specifiable — the standard part is where it starts, not where it stops. Made by cold heading or warm forging.
Minimum order from 2,000 pieces; samples within 7 days of drawing approval.
Custom screw manufacturingSend a drawing
Applications & Industries
Where Five-Lobe Bottom Service Screws for Mobile Devices are used, and what decides the specification in each case.
Industries that specify Five-Lobe Bottom Service Screws for Mobile Devices
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Smartphone service
Five-lobe screws retain the bottom edge where a five-lobe driver is specified.
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Consumer electronics repair
Short under-head lengths suit thin exterior panels.
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Device refurbishment
Model-matched replacement sets restore the original service interface.
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Mobile equipment labs
The small head and P2 drive fit a confined case edge.
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Maintenance & MRO
Stocked replacements matched to an existing property class, thread and finish.
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Food, pharma & cleanroom
Stainless assemblies that are washed down, where the finish matters as much as the strength.
Typical applications
- servicing a five-point bottom-edge screw with a P2 driver
- measuring the length under the head
- matching the replacement to the exact device model
- keeping the original head clearance at the case edge
- clamping two machined faces to a calculated preload
- bolting brackets, motors and gearboxes to a frame
Service conditions to specify against
- Marine and coastal
- Available in A4 (316) stainless for chloride exposure — coastal structures, pool halls, water treatment and deck hardware, where A2 will eventually pit.
- High load
- Supplied in ISO 898-1 property classes, so the joint can be designed to a stated proof load and tightened to a calculated torque rather than by feel.
- Torque and preload
- The joint is designed around bolt tension, so lubrication, coating and the friction coefficient all change the torque figure — state them together.
Where to use something else
- Do not replace a pentalobe screw with a Phillips screw simply because the diameter looks similar; the drive and length are different.
- Do not use a machine thread into unthreaded sheet or timber; use a tapping screw, rivet nut or insert made for that parent material.
Full application guide: where Five-Lobe Bottom Service Screws for Mobile Devices are used, how to specify them, and the cases they are wrong for
