Hotends & heat breaks (E3D and clones) screw size
M3 · 3 to 10 mm long
The screws used on Hotends & heat breaks (E3D and clones) are M3 in lengths from 3 to 10 mm.
Where it is used: heater block clamp, fan shroud, and headless grub screws.
Head and drive, as the source states them: set screw (headless) head.
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.
Hotends & heat breaks (E3D and clones) 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 | 3–10 mm | 0.5 mm | Set screw (headless) | not stated | heater block clamp, fan shroud, and headless grub screws | Confirmed |
Fitment records and sources
heater block clamp, fan shroud, and headless grub screws
pitch 0.5 mm · tap 2.5 mm · clearance 3.4 mm · PH1 / Torx T10
How to check the screw before you buy
- Take one original screw out first and measure it before ordering; the record above tells you the thread, the original screw tells you the exact length and head.
- 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: for set screw (headless) screws, measure from under the head to the tip (countersunk heads are the exception: they are measured overall).
- The records span 3–10 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
- Terminal-block clamp screws have manufacturer-specific torque values — over-tightening cracks the block or crushes the wire.
- Grub screws (set screws) on sensor retainers are frequently M3 even when the surrounding housing uses M4/M5 fasteners — don't assume one thread size for a whole enclosure.
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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M3 x 3mm Wafer Head Screws for Synology NAS Drive Canister 2.5 SSD Bay 10-Pack
$4.99 -
M3 x 3mm SSD Mounting Screws for HP Desktop 2.5 SATA Drive Replacement 10-Pack
$4.99 -
M3 x 4mm Phillips Wafer Head Screws for 2.5 SATA SSD Mounting 10-Pack
$4.99 -
M3 x 4mm Screws for Installing SSD into Synology NAS 10-Pack
$4.99 -
M3 x 5mm Phillips Wafer Head Screw for Electronics & Project Box Repair - Pack of 50 Black
$4.79 each · min. 2
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M3 x 8mm Phillips Flat Head Countersunk Machine Screws Zinc Silver 100-Pack for RC & 3D Printers
$9.99 -
M3 x 8mm Phillips Flat Head Countersunk Machine Screws Zinc Silver 10-Pack for RC & 3D Printers
$4.99 -
M3 x 4mm Phillips Wafer Head Screws for HDD Caddy Bracket 10-Pack
$4.99
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Devices whose records share a thread with Hotends & heat breaks (E3D and clones), closest length match first.
- Star Micronics mPOP under-counter mount (CM-POP1) also M3 × 8 mm
- Pumpkin SUPERNOVA 6U CubeSat Structure Kit also M3 × 8 mm
- Third-party Raspberry Pi cases & HAT stacks also M3 × 4–10 mm
- Takachi RPI aluminium Raspberry Pi case also M3 × 4 mm
- Backscatter FLIP3.1 underwater filter frame screws (2x) also M3 × 8 mm
- Novanta NEMA 23 stepper motor (3 A variant) also M3 × 3.18 mm
- Fluke 117 multimeter also M3 × 6 mm
- Floyd Rose locking tremolo saddles also M3 × 8 mm
Questions about Hotends & heat breaks (E3D and clones) screws
- What size screw does Hotends & heat breaks (E3D and clones) use?
- M3 × 3–10 mm for heater block clamp, fan shroud, and headless grub screws.
- How long are the screws in Hotends & heat breaks (E3D and clones)?
- The records range from 3 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 Hotends & heat breaks (E3D and clones)?
- 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 Hotends & heat breaks (E3D and clones)?
- TechSpareWarehouse (our own store) lists M3 x 3mm, M3 x 4mm and M3 x 5mm, which match lengths in the records above.