How long are the screws in Arduino Uno / shield mounting holes?

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 Arduino Uno / shield mounting holes?

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 Arduino Uno / shield mounting holes?

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

Arduino Uno / shield mounting holes screw size

M3 · 6 to 10 mm long

If you are replacing a screw on Arduino Uno / shield mounting holes, the thread is M3 in lengths from 6 to 10 mm.

Where it is used: official mechanical drawing shows M3-class mounting holes.

This entry is marked reported and comes from cdn-shop.adafruit.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.

Arduino Uno / shield mounting holes 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	Official mechanical drawing shows M3-class mounting holes	Reported

Fitment records and sources

M36-10mmreported

Official mechanical drawing shows M3-class mounting holes

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

Cleanroom/vacuum-rated M3 screws (titanium, vented, low-outgas) from NBK are a distinct specialty class, priced and sourced very differently from commodity M3 hardware — do not substitute one for the other in semiconductor fixtures.
M3 (3.0mm, 0.5mm pitch) is not #6-32 UNC (~3.5mm) — they look identical and cross-thread, the single most common PC-building mistake.

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 Arduino Uno / shield mounting holes, closest length match first.

Voron 2.4 3D printer also M3 × 8–10 mm
Ender 3 V3 KE cooling fan brackets also M3 × 8 mm
Linear rail carriage block also M3 × 6–8 mm
Carbide3D Shapeoko 5 Pro CNC router also M3 × 6 mm
FDM hotend and extruder mounts (general) also M3 × 8–10 mm
Ultimaker Original heated bed / Z-stage upgrade kit also M3 × 10 mm
Prusa MK4 Nextruder also M3 × 10 mm
Voron 2.4 electronics bay also M3 × 6–10 mm

Questions about Arduino Uno / shield mounting holes screws

What size screw does Arduino Uno / shield mounting holes use?: M3 × 6–10 mm for official mechanical drawing shows M3-class mounting holes.
How long are the screws in Arduino Uno / shield mounting holes?: 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 Arduino Uno / shield mounting holes?: 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 Arduino Uno / shield mounting holes?: TechSpareWarehouse (our own store) lists M3 x 6mm, M3 x 8mm and M3 x 10mm, which match lengths in the records above.

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