How long are the screws in Dell/HP SFF 2.5-inch drive tray?

The record gives 4 mm. Measure the original from under the head (overall for a countersunk head) to confirm before ordering.

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 Dell/HP SFF 2.5-inch drive tray?

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 Dell/HP SFF 2.5-inch drive tray?

TechSpareWarehouse (our own store) lists M3 x 4mm, which matches the length in the records above.

Dell/HP SFF 2.5-inch drive tray screw size

M3 · 4 mm long

Dell/HP SFF 2.5-inch drive tray takes M3 metric screws, 4 mm long.

Where it is used: countersunk M3 x 4mm screws for Dell and HP 2.5-inch drive trays.

Head and drive, as the source states them: flat / countersunk head.

This entry is marked reported and comes from disctech.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.

Dell/HP SFF 2.5-inch drive tray 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 mm	0.5 mm	Flat / countersunk	not stated	Countersunk M3 x 4mm screws for Dell and HP 2.5-inch drive trays	Reported

Fitment records and sources

M34mmreported

Countersunk M3 x 4mm screws for Dell and HP 2.5-inch drive trays

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

Source

How to check the screw before you buy

Rack and enclosure hardware mixes metric and imperial (#8-32, #10-32, #6-32), so confirm the thread before forcing a screw.
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: the source describes a countersunk (flat) head, and those are measured overall, from the top of the head to the tip.
The record states 4 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 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

Server drive caddy screws (Dell, HP) are usually M3 in very short lengths (3-4mm) because they bite into thin sheet metal — they are NOT the 6-32 UNC screws that go into the drive's own side holes.
ISO 14581 Torx countersunk screws look like plain countersunk screws but need the right lobe driver; a Phillips bit will chew the head.

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 Dell/HP SFF 2.5-inch drive tray, closest length match first.

Network switch & patch panel internals also M3 × 4 mm
Oracle MICROS Universal PED kiosk mount also M3 × 4 mm
2.5in SATA / SAS hard drives and SSDs (SFF-8201) also M3 × 4 mm
cab Applicator A3200 print-and-apply labeling system (packaging line hardware) also M3 × 4 mm
Cognex In-Sight 8000/8200/8400 vision system also M3 × 4 mm
2.5in SFF drive trays (Dell & HP server/SFF trays) also M3 × 4 mm
PEM KFE-M3-4ET broaching standoff also M3 × 4 mm
Mean Well NMP650 / NMP1K2 modular power supply also M3 × 4 mm

Questions about Dell/HP SFF 2.5-inch drive tray screws

What size screw does Dell/HP SFF 2.5-inch drive tray use?: M3 × 4 mm for countersunk M3 x 4mm screws for Dell and HP 2.5-inch drive trays.
How long are the screws in Dell/HP SFF 2.5-inch drive tray?: The record gives 4 mm. Measure the original from under the head (overall for a countersunk head) to confirm before ordering.
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 Dell/HP SFF 2.5-inch drive tray?: 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 Dell/HP SFF 2.5-inch drive tray?: TechSpareWarehouse (our own store) lists M3 x 4mm, which matches the length in the records above.

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