Robot Micro Screws CM2/CM2.5/CM3 | M2-M3 High-Strength Screws

M2–M3 screws for humanoid and collaborative robot joints, built for preload and fatigue rather than static load.

Key specifications

Size rangeM2-M3 (M4 on request)
MaterialSCM435 chrome-molybdenum steel
FinishZinc-nickel (black oxide, Geomet, DLC optional)
Installationtorque-controlled driver at the joint rating
StandardGB/T 3098.1, ISO 16047 (torque/clamp force)
Typical substraterobot joints, harmonic drives, dexterous hands

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Product overviewOverview

A robot joint does not see a static load; it sees a reversing load tens of times a minute. Under that regime a screw fails from a fatigue crack at the thread root long before it reaches its static strength. Robot-grade micro screws therefore differ from ordinary electronics screws: SCM435 chromium-molybdenum steel quenched and tempered to class 10.9 or 12.9, a larger root radius, and surface treatment that raises the fatigue limit.

This page covers M2-M3 (M4 on request) in SCM435 chrome-molybdenum steel, with zinc-nickel (black oxide, geomet, dlc optional) as the standard finish.property class 10.9 / 12.9; installed by torque-controlled driver at the joint rating.

Key featuresFeatures

SCM435 quenched and tempered to class 10.9 or 12.9, verified to GB/T 3098.1.
Enlarged thread root radius lowers stress concentration under reversing load.
Locking patch or disc spring compensates preload loss from thermal cycling.
6g threads and controlled straightness hold joint concentricity.

Typical applicationsApplications

Humanoid robot joints and harmonic drives
Collaborative robot arm joints
Dexterous hand fingers and linkages

Selection notesSelection

Set preload to the gearbox maker's rating; exceeding 70% of yield shortens fatigue life sharply.

Frequently asked questionsFAQ

How do I specify the Robot Micro Screws CM2/CM2.5/CM3 | M2-M3 High-Strength Screws?

Set preload to the gearbox maker's rating; exceeding 70% of yield shortens fatigue life sharply. This page covers M2-M3 (M4 on request) in SCM435 chrome-molybdenum steel, with zinc-nickel (black oxide, geomet, dlc optional) as the standard finish.property class 10.9 / 12.9; installed by torque-controlled driver at the joint rating.

What matters during installation of the Robot Micro Screws CM2/CM2.5/CM3 | M2-M3 High-Strength Screws?

Run the driver at the torque setting rated for the joint. SCM435 quenched and tempered to class 10.9 or 12.9, verified to GB/T 3098.1.

Specifications

Size range	M2-M3 (M4 on request)
Material	SCM435 chrome-molybdenum steel
Property class	10.9 / 12.9
Finish	Zinc-nickel (black oxide, Geomet, DLC optional)
Head styles	CM cheese head / FM flat head / countersunk
Drive	Phillips, hex socket, TORX
Standards	GB/T, ISO
Standard	GB/T 3098.1, ISO 16047 (torque/clamp force)
Installation	torque-controlled driver at the joint rating
Typical substrate	robot joints, harmonic drives, dexterous hands

Manufacturing and inspection

Tensile strength, yield strength and elongation are verified to GB/T 3098.1, with retained samples per lot.We recommend a pilot assembly at the actual torque and mating part before locking the process parameters for volume.