Lenovo ThinkPad X-series bottom cover screw size
M2.5 · 3.5 mm long
Lenovo ThinkPad X-series bottom cover takes M2.5 metric screws, 3.5 mm long.
The record covers nylon-coated flat head, same family as the T-series.
Head and drive, as the source states them: flat / countersunk head.
This entry is marked reported and comes from manualslib.com.
An M2.5 screw is 2.5 mm in diameter with a 0.45 mm pitch, tapped with a 2.05 mm drill; imperial look-alike: #3-48 / #4-40 (2.51 / 2.84 mm) — #4-40 is the common US stand-in and it will NOT thread in.
Lenovo ThinkPad X-series bottom cover 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 |
|---|---|---|---|---|---|---|
| M2.5 | 3.5 mm | 0.45 mm | Flat / countersunk | not stated | nylon-coated flat head, same family as the T-seriesthread-locking patch | Reported |
Fitment records and sources
nylon-coated flat head, same family as the T-series
pitch 0.45 mm · tap 2.05 mm · clearance 2.9 mm · PH1 / Torx T8
How to check the screw before you buy
- A screw that is even 1 mm too long in a laptop base can push into the keyboard, battery or a board trace, so match the length position by position.
- Diameter: across the threads an M2.5 screw measures about 2.5 mm with calipers (usually a hair under). If yours measures noticeably more or less, it is a different thread.
- Pitch: 0.45 mm from one thread crest to the next (22.22 crests per centimetre). A thread pitch gauge or the pitch-gauge tool settles it in seconds.
- Length: the source describes a countersunk (flat) head, and those are measured overall, from the top of the head to the tip.
- The record states 3.5 mm. Going longer risks bottoming out or touching parts behind the hole; going shorter loses thread engagement.
- Driver: the source does not name the drive. Standard M2.5 heads take PH1 for Phillips and T8 for Torx, and a 2 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 M2.5 is about 45-70 N·cm into metal threads and 20-35 N·cm into plastic bosses; snug it up and stop.
Common mix-ups with M2.5
- Nylon-coated M2.5 screws (ThinkPad Edge) are thread-locking; plain replacements work loose over time.
- Dell/HP/Lenovo manuals often list screws only by torque or head shape, so community teardowns are needed for diameter.
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Devices whose records share a thread with Lenovo ThinkPad X-series bottom cover, closest length match first.
- HP 255 G5 also M2.5 × 3.5 mm
- HP 255 G4 also M2.5 × 3.5 mm
- Lenovo ThinkPad L540 also M2.5 × 3.5 mm
- Lenovo LOQ 15APH8 also M2.5 × 3.5 mm
- Acer Aspire 4020/5510 series screw list also M2.5 × 3.5 mm
- Lenovo Legion Y7000P-1060 also M2.5 × 3.5 mm
- HP 16-d1000 (ids 2100286869 also M2.5 × 3.5 mm
- Dell Inspiron 13 7390 2-in-1 also M2.5 × 3.5 mm
Questions about Lenovo ThinkPad X-series bottom cover screws
- What size screw does Lenovo ThinkPad X-series bottom cover use?
- M2.5 × 3.5 mm for nylon-coated flat head, same family as the T-series.
- How long are the screws in Lenovo ThinkPad X-series bottom cover?
- The record gives 3.5 mm. Measure the original from under the head (overall for a countersunk head) to confirm before ordering.
- What is the thread pitch of an M2.5 screw?
- 0.45 mm (coarse), which is the standard pitch for M2.5 machine screws; a 0.35 mm fine pitch exists but is uncommon. The tap drill is 2.05 mm and the normal clearance hole is 2.9 mm.
- What screwdriver do I need for Lenovo ThinkPad X-series bottom cover?
- The sources do not name the drive. For M2.5, Phillips heads normally take PH1 and Torx heads T8; socket heads take a 2 mm hex key.
- Can I use an imperial screw instead of M2.5?
- No. Imperial look-alike: #3-48 / #4-40 (2.51 / 2.84 mm) — #4-40 is the common US stand-in and it will NOT thread in. Use a true M2.5 screw so it does not cross-thread or strip the hole.