What size screw does Bambu Lab X1/P1/AMS spare screw kit use?

M3 × 4–20 mm for official spares kit is predominantly M3 sizes.

How long are the screws in Bambu Lab X1/P1/AMS spare screw kit?

The records range from 4 to 20 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 Bambu Lab X1/P1/AMS spare screw kit?

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 Bambu Lab X1/P1/AMS spare screw kit?

TechSpareWarehouse (our own store) lists M3 x 4mm, M3 x 5mm and M3 x 6mm, which match lengths in the records above.

Bambu Lab X1/P1/AMS spare screw kit screw size

M3 · 4 to 20 mm long

The screws used on Bambu Lab X1/P1/AMS spare screw kit are M3 in lengths from 4 to 20 mm.

It is listed for official spares kit is predominantly M3 sizes.

This entry is marked reported and comes from us.store.bambulab.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.

Bambu Lab X1/P1/AMS spare screw kit 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	4–20 mm	0.5 mm	not stated	not stated	Official spares kit is predominantly M3 sizes	Reported

Fitment records and sources

M34-20mmreported

Official spares kit is predominantly M3 sizes

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 4–20 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.
Some sewing-machine screws are labeled with metric-looking but slightly nonstandard sizes (e.g. M3.3) that are not true ISO M3 and are not interchangeable with standard M3 hardware.

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 Bambu Lab X1/P1/AMS spare screw kit, closest length match first.

Robotiq low-profile gripper coupling also M3 × 5 mm
CNC / V-slot limit switches & sensors also M3 × 6–10 mm
Arduino shield stacking standoffs also M3 × 8–11 mm
Heated bed to Y-carriage also M3 × 16–20 mm
GT2 timing pulley grub screws also M3 × 4–6 mm
Voron 2.4 / Trident also M3 × 6–20 mm
Voron 2.4 gantry and carriage hardware also M3 × 6–20 mm
Voron StealthBurner toolhead (stock hotend) also M3 × 8 mm

Questions about Bambu Lab X1/P1/AMS spare screw kit screws

What size screw does Bambu Lab X1/P1/AMS spare screw kit use?: M3 × 4–20 mm for official spares kit is predominantly M3 sizes.
How long are the screws in Bambu Lab X1/P1/AMS spare screw kit?: The records range from 4 to 20 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 Bambu Lab X1/P1/AMS spare screw kit?: 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 Bambu Lab X1/P1/AMS spare screw kit?: TechSpareWarehouse (our own store) lists M3 x 4mm, M3 x 5mm and M3 x 6mm, which match lengths in the records above.

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