What size screw does Prusa MK4 Nextruder use?

M3 × 10–40 mm for hotend and fan shroud mounting.

How long are the screws in Prusa MK4 Nextruder?

The records range from 10 to 40 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 Prusa MK4 Nextruder?

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 Prusa MK4 Nextruder?

TechSpareWarehouse (our own store) lists M3 x 10mm, M3 x 12mm and M3 x 14mm, which match lengths in the records above.

Prusa MK4 Nextruder screw size

M3 · 10 to 40 mm long

Prusa MK4 Nextruder takes M3 metric screws in lengths from 10 to 40 mm.

Where it is used: hotend and fan shroud mounting.

This entry is marked confirmed and comes from help.prusa3d.com.

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.

Prusa MK4 Nextruder 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	10–40 mm	0.5 mm	not stated	not stated	hotend and fan shroud mounting	Confirmed

Fitment records and sources

M310-40mmconfirmed

hotend and fan shroud mounting

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

Source

How to check the screw before you buy

Into printed plastic, the screw either self-taps or needs a heat-set insert; machine screws straight into plastic strip easily.
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 10–40 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

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.

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 12mm Phillips Wafer Head Screw for Camera Cage & Battery Slide Mount - Pack of 50 Black $6.49
M3 x 12mm Phillips Wafer Head Screw for Electric Scooter LCD Dashboard - Single Replacement Black $0.10 each · min. 50
M3 x 14mm Phillips Wafer Head Screw for Camera Cage & Battery Slide Mount - Pack of 50 Black $6.99
M3 x 14mm Phillips Wafer Head Screw for 3D Printer Extruder Stepper Motor - Single Replacement Black $0.10 each · min. 50
M3 x 10mm Phillips Wafer Head Screw for 3D Printer Frame Assembly - Single Replacement Black $0.10 each · min. 50
M3 x 12mm Phillips Wafer Head Screw for RC Car/Truck Chassis Mount - Single Replacement Black $0.10 each · min. 50

More in 3D Printing, CNC & Robotics

2020 extrusion T-nuts (light duty)2020 extrusion T-nuts (standard)2020 T-slot hammer head bolts 2020/2040 extrusion end tap 2040 extrusion T-nuts 3030 extrusion T-nuts (heavy duty)3030/4040 extrusion end tap 3D printer & CNC enclosures 3D printer hotend to X-carriage Actobotics servo horn / hub Arduino Mega 2560 mounting holes Arduino shield stacking standoffs

Browse all 149 in 3D Printing, CNC & Robotics →

The same screw also fits

Devices whose records share a thread with Prusa MK4 Nextruder, closest length match first.

Voron Stealthburner toolhead also M3 × 10–16 mm
Voron 2.4 electronics bay also M3 × 10 mm
Ultimaker Original heated bed / Z-stage upgrade kit also M3 × 10–25 mm
InMoov open-source robot also M3 × 20 mm
NEMA 17 stepper motor mounting also M3 × 10–14 mm
Bambu Lab X1/P1 heatbed transport anchors also M3 × 20–23 mm
Bambu Lab X1/P1 General machine screws throughout the printer also M3 × 10 mm
REV Robotics hex standoffs also M3 × 15 mm

Questions about Prusa MK4 Nextruder screws

What size screw does Prusa MK4 Nextruder use?: M3 × 10–40 mm for hotend and fan shroud mounting.
How long are the screws in Prusa MK4 Nextruder?: The records range from 10 to 40 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 Prusa MK4 Nextruder?: 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 Prusa MK4 Nextruder?: TechSpareWarehouse (our own store) lists M3 x 10mm, M3 x 12mm and M3 x 14mm, which match lengths in the records above.

Heads up: shipping delay