Property Class 12.9 Steel Fitted (Reamer) Bolts, DIN 609 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.
Material specification page for fitted (reamer) bolts, din 609 in Property Class 12.9 Steel. Covers the grade designation (ISO 898-1 property class 12.9), corrosion and magnetic behavior, comparable grades and their trade-offs, and the sizes available to DIN 609.
Why Choose Property Class 12.9 Steel for Fitted (Reamer) Bolts, DIN 609
The highest common strength class, for high-load machine assembly. For fitted (reamer) bolts, din 609, 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 |
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| Service temperature | commonly limited to approx. +300 °C; confirm against the coating and the load |
|---|
| Corrosion characteristic | Requires plating or black-oxide protection |
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Corrosion Behavior in Service
Carbon and alloy steel fitted (reamer) bolts, din 609 require a coating for corrosion protection. Zinc plating (with or without passivation) is the most common; hot-dip galvanizing is used for outdoor structural service; black-oxide is mainly a tarnish-prevention finish for tool-room use.
Comparable Grades
For Fitted (Reamer) Bolts, DIN 609, 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 Fitted (Reamer) Bolts, DIN 609 Available in Property Class 12.9 Steel
| Thread size | Shank diameter ds k6 (mm) | Reamed hole H7 (mm) | Width across flats s (mm) | Head height k (mm) | Common length range (mm) | Property class | Reference standard |
|---|
| M8 | 9 | 9 | 13 | 5.3 | 30~80 | 8.8 | DIN 609 |
| M10 | 11 | 11 | 17 | 6.4 | 35~100 | 8.8 | DIN 609 |
| M12 | 13 | 13 | 19 | 7.5 | 40~120 | 8.8 | DIN 609 |
| M16 | 17 | 17 | 24 | 10.0 | 50~150 | 8.8 | DIN 609 |
| M20 | 21 | 21 | 30 | 12.5 | 60~180 | 8.8 | DIN 609 |
| M24 | 25 | 25 | 36 | 15.0 | 70~200 | 8.8 | DIN 609 |
Dimensions are independent of the material: every size above is available in Property Class 12.9 Steel.
Custom manufacturing · Made to drawing
Need this bolt in a grade that is not listed?
Grade 12 9 Steel is one of the grades the catalog describes. Lengths and thread lengths outside the standard table are the commonest request, followed by a drive the standard does not offer and a head marked with your own part number. Made by cold heading or hot forging.
Minimum order from 2,000 pieces; samples within 7 days of drawing approval.
Custom bolt manufacturingSend a drawing
Applications & Industries
Fitted Bolts are bought for a small number of well-defined jobs. These are the ones we ship them for. Stocked from M8 to M24.
Industries that specify Fitted Bolts
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Gearbox & housing assembly
Split housings that must reassemble in exactly the same position.
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Press & die sets
Located joints carrying shear across the parting line.
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Machine tools
Joints where the bolt locates the two halves as well as clamping them.
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Automotive & transport
Chassis, driveline and body fixings that see vibration and are assembled to a controlled preload.
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Steel fabrication
Bolted connections in frames, enclosures, walkways and weldments, on the bench and on site.
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Energy & infrastructure
Tower, pipework, switchgear and plant fixings specified for long service life and inspectable joints.
Typical applications
- locating two parts within a few hundredths of a millimetre
- reamed H7 holes matched to a k6 ground shank
- transmitting shear on the shank rather than by friction
- joints where the property class is stated on the drawing
- 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 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 Fitted Bolts are used, how to specify them, and the cases they are wrong for
