What to Know Before You Install M12-1.75 x 25mm Flat Head Socket Cap Screws
Flat head socket cap screws are designed to sit flush with the surface after installation. For the M12-1.75 x 25mm size, the combination of a flat head, hex socket drive, and fully threaded shank makes them a good fit for machinery, tooling, jigs, and precision assemblies where a low-profile finish is needed. Before you start, confirm that your application can accept a 25mm screw length and that the M12-1.75 thread pitch matches your tapped hole or nut.
Product Specifications for M12-1.75 x 25mm Flat Head Socket Cap Screws
- M12-1.75 X 25mm Socket Cap Screws | Flat Head Hex Socket Drive | Fully Threaded | Class 12.9 Alloy Steel Thermal Black Oxide (100 / Pkg.): These M12-1.75 x 25mm socket cap screws are manufactured from Alloy Steel Thermal Black Oxide, featuring a hex socket drive. Confirms the screw material and finish, which affect corrosion resistance and appearance.
M12-1.75 X 25mm Socket Cap Screws | Flat Head Hex Socket Drive | Fully Threaded | Class 12.9 Alloy Steel Thermal Black Oxide (100 / Pkg.) - M12-1.75 X 25mm Socket Cap Screws | Flat Head Hex Socket Drive | Fully Threaded | Class 12.9 Alloy Steel Thermal Black Oxide (100 / Pkg.): Material and finish: Alloy Steel Thermal Black Oxide Thermal black oxide provides a mild corrosion-resistant layer and a non-reflective surface.
- M12-1.75 X 25mm Socket Cap Screws | Flat Head Hex Socket Drive | Fully Threaded | Class 12.9 Alloy Steel Thermal Black Oxide (100 / Pkg.): Thread size: M12-1.75, Length: 25mm, Grade: Class 12.9 Class 12.9 is a high-strength alloy steel grade; the M12-1.75 thread is a coarse metric thread.
- M12-1.75 X 25mm Socket Cap Screws | Flat Head Hex Socket Drive | Fully Threaded | Class 12.9 Alloy Steel Thermal Black Oxide (100 / Pkg.): Head style: Flat Head, Drive: Hex Socket Drive, Thread style: Fully Threaded Flat head allows countersinking; hex socket drive reduces cam-out risk; fully threaded provides maximum thread engagement.
- M12-1.75 X 25mm Socket Cap Screws | Flat Head Hex Socket Drive | Fully Threaded | Class 12.9 Alloy Steel Thermal Black Oxide (100 / Pkg.): Pack quantity: 100 per package Buying in bulk reduces per-unit cost and ensures you have spares for the job.
Step-by-Step Installation for Flat Head Socket Cap Screws
- 1. Prepare the mating hole or nut: Ensure the hole or nut is tapped to M12-1.75. For countersinking, the hole must be chamfered to accept the flat head so the screw sits flush or slightly below the surface.
- 2. Select the correct hex key: Use a hex key (Allen wrench) that fits the hex socket drive snugly. A worn or incorrect size can strip the socket. The hex size is not listed in the supplied catalog; verify fit before applying torque.
- 3. Hand-start the screw: Thread the screw by hand for the first few turns to confirm alignment and avoid cross-threading. The fully threaded design engages immediately, so misalignment can cause thread damage.
- 4. Apply torque gradually: Tighten with a torque wrench set to the manufacturer's specification for Class 12.9 alloy steel M12 fasteners. The catalog does not supply a specific torque value; refer to your assembly's engineering specs. Over-torquing can strip the threads or break the screw.
- 5. Check the final seating: The flat head should sit flush with the surface. If it protrudes, the countersink may be too shallow. If it sinks below the surface, the countersink may be too deep or the screw length incorrect.
Material and Finish Considerations
Class 12.9 alloy steel is a high-strength material, but it is not stainless. The thermal black oxide finish offers some corrosion protection, but it is not suitable for wet or corrosive environments without additional coating or sealing. For indoor machinery, tooling, and jigs, this finish is typically adequate. The black oxide also reduces glare, which can be helpful in precision assembly work.
What the Catalog Does Not Tell You
The catalog does not specify the hex socket size, recommended torque range, or maximum load capacity. For critical applications, consult the screw manufacturer's technical data or test a sample in your assembly. The flat head's countersink angle is also not listed; you may need to measure the head angle or use a trial fit to determine the correct chamfer.
