What is the thread pitch of an M3 screw?

0.5 mm (coarse), which is the standard pitch for M3 machine screws; a 0.35 mm fine pitch exists but is uncommon. The tap drill is 2.5 mm and the normal clearance hole is 3.4 mm.

Can I use an imperial screw instead of M3?

No. Imperial look-alike: #5-40 (3.18 mm) or #4-40 — neither interchanges with M3. Use a true M3 screw so it does not cross-thread or strip the hole.

COSEL power supply terminal block (used in industrial/pump/water-treatment control panels) screw size

M3 · 6 to 8 mm long

If you are replacing a screw on COSEL power supply terminal block (used in industrial/pump/water-treatment control panels), the thread is M3 in lengths from 6 to 8 mm.

It is listed for COSEL's official terminal block torque FAQ explicitly lists M3 screw diameter with recommended torque 0.36-0.6 N·m for terminal block connections used across their industrial power supplies.

This entry is marked confirmed and comes from cosel.com.

An M3 screw is 3 mm in diameter with a 0.5 mm pitch, tapped with a 2.5 mm drill; imperial look-alike: #5-40 (3.18 mm) or #4-40 — neither interchanges with M3.

COSEL power supply terminal block (used in industrial/pump/water-treatment control panels) screw specifications

One row per fitment record. Head, drive and torque are shown only where the source states them; pitch is the ISO coarse pitch for the thread.

Thread	Length	Pitch	Head	Drive	Torque	Where it goes	Status
M3	6–8 mm	0.5 mm	not stated	not stated	0.36-0.6 N·m	COSEL's official terminal block torque FAQ explicitly lists M3 screw diameter with recommended torque 0.36-0.6 N·m for terminal block connections used across their industrial power supplies	Confirmed

Fitment records and sources

M3M3x6-M3x8confirmed

COSEL's official terminal block torque FAQ explicitly lists M3 screw diameter with recommended torque 0.36-0.6 N·m for terminal block connections used across their industrial power supplies

pitch 0.5 mm · tap 2.5 mm · clearance 3.4 mm · PH1 / Torx T10

Source

How to check the screw before you buy

Industrial parts lists usually give the full callout (thread, length, head, grade); match all four, not just the thread.
Diameter: across the threads an M3 screw measures about 3 mm with calipers (usually a hair under). If yours measures noticeably more or less, it is a different thread.
Pitch: 0.5 mm from one thread crest to the next (20 crests per centimetre). A thread pitch gauge or the pitch-gauge tool settles it in seconds.
Length: measure from under the head to the tip for pan, button, wafer and cap heads; countersunk (flat) heads are measured overall.
The records span 6–8 mm, which means different positions take different lengths — match each hole to its own screw.
Driver: the source does not name the drive. Standard M3 heads take PH1 for Phillips and T10 for Torx, and a 2.5 mm hex key for socket heads; a bit that fits loosely will cam out and strip the head.

Common mix-ups with M3

DIN-rail terminal blocks are near-universally M3 across Dinkle, TE, Omron and RND, but torque differs (0.5-0.8 Nm) — over-torquing an M3 terminal screw strips it instantly.
Terminal-block clamp screws have manufacturer-specific torque values — over-tightening cracks the block or crushes the wire.

Pitch gauge · Screw size finder · Torque guide

Buy these screws at TechSpare Warehouse

In stock and shipped from South Carolina. Our black screws are Phillips wafer head (low profile); match the head style and length to the original before you order.

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The same screw also fits

Devices whose records share a thread with COSEL power supply terminal block (used in industrial/pump/water-treatment control panels), closest length match first.

Diebold Nixdorf ATM currency stacker (PN 29016399000B) also M3 × 6 mm
Juki MF-7900 industrial coverstitch machine also M3 × 8 mm
Power tool trigger switch also M3 × 8 mm
GCX barcode scanner adapter kit also M3 × 6 mm
Happy HCR Series Computerized Embroidery Machine also M3 × 6 mm
Milwaukee M18/M12 charger and cordless tool internals also M3 × 8 mm
Smart home sensor brackets also M3 × 6–8 mm
Creality Ender 3 (non-frame parts) also M3 × 6–8 mm

Questions about COSEL power supply terminal block (used in industrial/pump/water-treatment control panels) screws

What size screw does COSEL power supply terminal block (used in industrial/pump/water-treatment control panels) use?: M3 × 6–8 mm for COSEL's official terminal block torque FAQ explicitly lists M3 screw diameter with recommended torque 0.36-0.6 N·m for terminal block connections used across their industrial power supplies.
How long are the screws in COSEL power supply terminal block (used in industrial/pump/water-treatment control panels)?: The records range from 6 to 8 mm depending on the position, so match each screw to its own hole.
What is the thread pitch of an M3 screw?: 0.5 mm (coarse), which is the standard pitch for M3 machine screws; a 0.35 mm fine pitch exists but is uncommon. The tap drill is 2.5 mm and the normal clearance hole is 3.4 mm.
What screwdriver do I need for COSEL power supply terminal block (used in industrial/pump/water-treatment control panels)?: The sources do not name the drive. For M3, Phillips heads normally take PH1 and Torx heads T10; socket heads take a 2.5 mm hex key.
Can I use an imperial screw instead of M3?: No. Imperial look-alike: #5-40 (3.18 mm) or #4-40 — neither interchanges with M3. Use a true M3 screw so it does not cross-thread or strip the hole.
How tight should the M3 screw on COSEL power supply terminal block (used in industrial/pump/water-treatment control panels) be?: The source gives 0.36-0.6 N·m for COSEL's official terminal block torque FAQ explicitly lists M3 screw diameter with recommended torque 0.36-0.6 N·m for terminal block connections used across their industrial power supplies.
Where can I buy replacement screws for COSEL power supply terminal block (used in industrial/pump/water-treatment control panels)?: TechSpareWarehouse (our own store) lists M3 x 6mm and M3 x 8mm, which match lengths in the records above.

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