Lenovo ThinkPad E490s and S3 screw size

Lenovo ThinkPad E490s and S3 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.

How to check the screw before you buy

1. 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.
2. Diameter: across the threads an M2 screw measures about 2 mm with calipers (usually a hair under). This device also uses M2.5, so measure each screw rather than assuming they match.
3. Pitch: 0.4 mm from one thread crest to the next (25 crests per centimetre). A thread pitch gauge or the pitch-gauge tool settles it in seconds.
4. Length: the source describes a countersunk (flat) head, and those are measured overall, from the top of the head to the tip.
5. The records span 2–5 mm, which means different positions take different lengths — match each hole to its own screw.
6. Driver: the source does not name the drive. Standard M2 heads take PH0 for Phillips and T6 for Torx, and a 1.5 mm hex key for socket heads; a bit that fits loosely will cam out and strip the head.
7. Tightening: no device-specific torque is published in these records. The site's general figure for M2 is about 25-40 N·cm into metal threads and 12-20 N·cm into plastic bosses; snug it up and stop.

Pitch gauge · Screw size finder · Torque guide

More in Laptops & PCs

The same screw also fits

Devices whose records share a thread with Lenovo ThinkPad E490s and S3, closest length match first.

• Dell Latitude E6400 XFR also M2.5 × 5 mm
• Lenovo V330 also M2 × 2.5 mm
• Dell Inspiron 15 5591 2-in-1 also M2 × 2.5 mm
• Dell Alienware m18 R2 also M2 × 2.5 mm
• Dell Precision 3580 also M2 × 2.5 mm
• Dell Latitude D630C also M2.5 × 5 mm
• Acer Aspire 4710G also M2 × 2.5 mm
• Dell Latitude 5424 also M2.5 × 5 mm

Questions about Lenovo ThinkPad E490s and S3 screws

What size screw does Lenovo ThinkPad E490s and S3 use?

M2 × 2.5 mm for internal FRU screw listed in the official Hardware Maintenance Manual screw tables — flat-head, 2.5mm long; M2 × 2.5 mm for wireless LAN card — flat-head screw, 2.5mm long (official Hardware Maintenance Manual screw table); M2 × 4 mm for I/O card — flat-head screw, 4mm long (official Hardware Maintenance Manual screw table); M2 × 2 mm for I/O card — flat-head screw, 2mm long (official Hardware Maintenance Manual screw table); M2 × 4 mm for internal FRU screw listed in the official Hardware Maintenance Manual screw tables — small-head, 4mm long; M2 × 2 mm for fingerprint reader card — flat-head screw, 2mm long (official Hardware Maintenance Manual screw table); M2 × 2 mm for i.

How long are the screws in Lenovo ThinkPad E490s and S3?

The records range from 2 to 5 mm depending on the position, so match each screw to its own hole.

What is the thread pitch of an M2 screw?

0.4 mm (coarse), which is the standard pitch for M2 machine screws; a 0.25 mm fine pitch exists but is uncommon. The tap drill is 1.6 mm and the normal clearance hole is 2.4 mm.

What screwdriver do I need for Lenovo ThinkPad E490s and S3?

The sources do not name the drive. For M2, Phillips heads normally take PH0 and Torx heads T6; socket heads take a 1.5 mm hex key.

Can I use an imperial screw instead of M2?

No. Imperial look-alike: #2-56 UNC (2.18 mm) is close but not interchangeable. Use a true M2 screw so it does not cross-thread or strip the hole.

Where can I buy replacement screws for Lenovo ThinkPad E490s and S3?

TechSpareWarehouse (our own store) lists M2 x 2.5mm, M2 x 4mm and M2 x 2mm, which match lengths in the records above.