Property Class 8.8 Steel Inch Slotted Shoulder Screws are supplied to ISO 898-1 property class 8.8. Corrosion behaviour is requires plating (zinc) for corrosion 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 workhorse medium-carbon alloy class for structural joints.
- Grade
- ISO 898-1 property class 8.8
- Corrosion resistance
- Requires plating (zinc) for corrosion 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 inch slotted shoulder screws in Property Class 8.8 Steel. Covers the grade designation (ISO 898-1 property class 8.8), corrosion and magnetic behavior, comparable grades and their trade-offs, and the sizes available to Trade series (inch shoulder screws).
Why Choose Property Class 8.8 Steel for Inch Slotted Shoulder Screws
The workhorse medium-carbon alloy class for structural joints. For inch slotted shoulder screws, this matters when requires plating (zinc) for corrosion protection is the primary requirement.
Mechanical & Physical Properties
| Grade designation | ISO 898-1 property class 8.8 |
|---|
| Magnetic response | Magnetic |
|---|
| Service temperature | commonly limited to approx. +300 °C; confirm against the coating and the load |
|---|
| Corrosion characteristic | Requires plating (zinc) for corrosion protection |
|---|
Corrosion Behavior in Service
Carbon and alloy steel inch slotted shoulder screws 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 Inch Slotted Shoulder Screws, class 10.9 or 12.9 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 Inch Slotted Shoulder Screws Available in Property Class 8.8 Steel
| Shoulder diameter (in) | Thread options | Shoulder length (in) | Slot width (in) | Slot depth (in) | Material options | Thread class |
|---|
| 1/8 | #4-40 / #6-32 | 1/8~1-1/2 | 0.047~0.094 | 0.062~0.109 | 303 or 416 stainless / alloy steel / brass | 2A |
| 1/4 | #8-32 / #10-24 / #10-32 | 1/8~1-1/2 | 0.047~0.094 | 0.062~0.109 | 303 or 416 stainless / alloy steel / brass | 2A |
| 3/8 | 1/4-20 / 5/16-18 | 1/8~1-1/2 | 0.047~0.094 | 0.062~0.109 | 303 or 416 stainless / alloy steel / brass | 2A |
| 1/2 | 3/8-16 | 1/8~1-1/2 | 0.047~0.094 | 0.062~0.109 | 303 or 416 stainless / alloy steel / brass | 2A |
Applications & Industries
Inch Slotted Shoulder Screws are bought for a small number of well-defined jobs. These are the ones we ship them for. Stocked from 1/8 to 1/2 (screw size).
Industries that specify Inch Slotted Shoulder Screws
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Light machinery
Wear-resistant pivot hardware assembled with a simple slot driver.
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Linkage mechanisms
Slotted-head shoulder screws used as pivots and bearing shoulders.
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Tooling fixtures
Replaceable guide and stop points in jigs.
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Camera and instrument mounts
Controlled shoulder length where axial position matters.
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Energy & infrastructure
Tower, pipework, switchgear and plant fixings specified for long service life and inspectable joints.
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Maintenance & MRO
Stocked replacements matched to an existing property class, thread and finish.
Typical applications
- keeping the mating part on the shoulder instead of the threaded section
- locating a rotating or sliding part on a defined cylindrical shoulder
- selecting shoulder diameter and length separately from the thread
- using the slot for low-profile manual assembly
- joints where the property class is stated on the drawing
- clamping two machined faces to a calculated preload
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 the slot as a high-torque structural drive; it is a compact head feature for the shoulder assembly.
- 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 Inch Slotted Shoulder Screws are used, how to specify them, and the cases they are wrong for
