How long are the screws in CNC / V-slot limit switches & sensors?

The records range from 6 to 10 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 CNC / V-slot limit switches & sensors?

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.

Where can I buy replacement screws for CNC / V-slot limit switches & sensors?

TechSpareWarehouse (our own store) lists M3 x 6mm, M3 x 8mm and M3 x 10mm, which match lengths in the records above.

CNC / V-slot limit switches & sensors screw size

M3 · 6 to 10 mm long

The screws used on CNC / V-slot limit switches & sensors are M3 in lengths from 6 to 10 mm.

It is listed for microswitch, sensor and cable-chain brackets on extrusion frames.

This entry is marked reported and comes from v3dp.ca.

For reference, M3 is 3 mm across the threads at 0.5 mm pitch. The imperial size people confuse it with: #5-40 (3.18 mm) or #4-40 — neither interchanges with M3.

CNC / V-slot limit switches & sensors screw specifications

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

Thread	Length	Pitch	Head	Drive	Where it goes	Status
M3	6–10 mm	0.5 mm	not stated	not stated	microswitch, sensor and cable-chain brackets on extrusion frames	Reported

Fitment records and sources

M36-10mmreported

microswitch, sensor and cable-chain brackets on extrusion frames

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

Source

How to check the screw before you buy

Printer and CNC builds usually publish a bill of materials; when it lists a length, follow it, since extrusion T-nuts and motor faces have fixed thread depths.
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 6–10 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.
Tightening: no device-specific torque is published in these records. The site's general figure for M3 is about 80-130 N·cm into metal threads and 35-60 N·cm into plastic bosses; snug it up and stop.

Common mix-ups with M3

Many gas-detector and sensor manuals only give a torque spec (e.g. '0.5 N·m max') without repeating the thread size at every mention — the explicit M3 callout is usually only in the accessories/spare-parts table, not the main installation steps.
2020 extrusion T-nuts come in M3/M4/M5 and are not interchangeable — M3 is accessory-only, M5 is structural.

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.

M3 x 6mm Replacement Screws for XLR Audio Connectors Phillips Wafer Head 50-Pack $4.99
M3 x 6mm Phillips Wafer Head Carbon Steel Machine Screws for XLR Audio Connectors | 50-Pack (Black) $4.99
M3 x 8mm Screws for Leather Spike Attachments Guitar Straps 10-Pack $4.99
M3 x 8mm Phillips Wafer Head Screw for SLA Resin 3D Printer VAT Film - Single Replacement Black $0.10 each · min. 50
M3 x 10mm Phillips Wafer Head Screw for Sim Racing Wheel Paddle Shifter - Single Replacement Black $0.10 each · min. 50
M3 x 10mm Phillips Wafer Head Screw for RC Car/Truck Chassis Mount - Single Replacement Black $0.10 each · min. 50
M3 x 6mm Phillips Wafer Head Screw for 3D Printer Frame Assembly - Single Replacement Black $0.10 each · min. 50
M3 x 6mm Phillips Wafer Head Screw for Boutique Guitar Pedal Enclosure - Single Replacement Black $0.10 each · min. 50

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The same screw also fits

Devices whose records share a thread with CNC / V-slot limit switches & sensors, closest length match first.

Bambu Lab X1/P1/AMS spare screw kit also M3 × 6–10 mm
Arduino shield stacking standoffs also M3 × 8–10 mm
Voron 2.4 gantry and carriage hardware also M3 × 6–10 mm
GT2 timing pulley grub screws also M3 × 6 mm
Voron 2.4 / Trident also M3 × 6–10 mm
Voron StealthBurner toolhead (stock hotend) also M3 × 8 mm
Bambu Lab X1 / P1 / A1 frame and toolhead also M3 × 6–10 mm
MGN9 linear rail also M3 × 6–8 mm

Questions about CNC / V-slot limit switches & sensors screws

What size screw does CNC / V-slot limit switches & sensors use?: M3 × 6–10 mm for microswitch, sensor and cable-chain brackets on extrusion frames.
How long are the screws in CNC / V-slot limit switches & sensors?: The records range from 6 to 10 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 CNC / V-slot limit switches & sensors?: 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.
Where can I buy replacement screws for CNC / V-slot limit switches & sensors?: TechSpareWarehouse (our own store) lists M3 x 6mm, M3 x 8mm and M3 x 10mm, which match lengths in the records above.

Heads up: shipping delay