SmallRig camera cages and rigs screw size
M2 / M2.5 / M3 · length not stated in the sources
If you are replacing a screw on SmallRig camera cages and rigs, the thread is M2, M2.5 and M3. None of the sources we found gives an exact length, so measure the original before you order.
There are 3 separate fitment records for it, including older-version gear lock screws take four M2; the 26-piece set covers M2-M4 plus 1/4in and (M2), cage side-lock hex socket screws, supplied as M2.5 in the MB2734 screw set (M2.5) and gear lock screws — four M3 on current gears (older gears take four M2); sets also include (M3).
Head and drive, as the sources state them: Hex socket (Allen) drive.
3 of the 3 records are marked confirmed, drawn from 2 sources (smallrig.com and smallrigreseller.com).
M2 means a 2 mm nominal diameter with a 0.4 mm thread pitch. Imperial look-alike: #2-56 UNC (2.18 mm) is close but not interchangeable.
SmallRig camera cages and rigs 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 | not stated | 0.4 mm | not stated | not stated | Older-version gear lock screws take four M2; the 26-piece set covers M2-M4 plus 1/4in and 3/8in | Confirmed |
| M2.5 | not stated | 0.45 mm | not stated | Hex socket (Allen) | Cage side-lock hex socket screws, supplied as M2.5 in the MB2734 screw set | Confirmed |
| M3 | not stated | 0.5 mm | not stated | Hex socket (Allen) | Gear lock screws — four M3 on current gears (older gears take four M2); sets also include M2.5 hex socket screws for cage side locks | Confirmed |
Fitment records and sources
Older-version gear lock screws take four M2; the 26-piece set covers M2-M4 plus 1/4in and 3/8in
pitch 0.4 mm · tap 1.6 mm · clearance 2.4 mm · PH0 / Torx T6
Cage side-lock hex socket screws, supplied as M2.5 in the MB2734 screw set
pitch 0.45 mm · tap 2.05 mm · clearance 2.9 mm · PH1 / Torx T8
Gear lock screws — four M3 on current gears (older gears take four M2); sets also include M2.5 hex socket screws for cage side locks
pitch 0.5 mm · tap 2.5 mm · clearance 3.4 mm · PH1 / Torx T10
How to check the screw before you buy
- Camera and optics hardware often uses short screws into thin threaded plates, so check engagement before tightening fully.
- Diameter: across the threads an M2 screw measures about 2 mm with calipers (usually a hair under). This device also uses M2.5 / M3, so measure each screw rather than assuming they match.
- 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.
- Length: measure from under the head to the tip for pan, button, wafer and cap heads; countersunk (flat) heads are measured overall.
- Driver: the source names a Hex socket (Allen) drive. For comparison, standard M2 heads take PH0 (Phillips) or T6 (Torx), or a 1.5 mm hex key.
- 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.
Common mix-ups with M2 / M2.5 / M3
- M2 (2.00mm, 0.4mm pitch) is NOT the same as #2-56 UNC (2.18mm) — close enough to cross-thread and strip if forced.
- Projector optics and fan screws often step down to M2.5 while the outer covers use M3 - do not reuse cover screws inside the light engine.
- Camera tripod and Arca threads are imperial 1/4-20 and 3/8-16, never M3.
More in Cameras & Optics
The same screw also fits
Devices whose records share a thread with SmallRig camera cages and rigs, closest length match first.
- SmallRig Cold Shoe Mount (2-pack, product 2060) also M2.5
- 1.25" eyepiece/diagonal/SCT visual back thumb screw also M3
- Camera hot shoe base plate also M2.5
- SIG SAUER ROMEO-RS reflex sight, mounting to SIG P365 pistol optic cut also M3
- Wimberley P-20 Arca-Swiss style tripod lens plate also M3
- SmallRig 4261 cage (Nikon Z f) also M2.5
- DJI Ronin 4D 6K also M2
- Microscope objective turret and stage also M3
Questions about SmallRig camera cages and rigs screws
- What size screw does SmallRig camera cages and rigs use?
- M2 for older-version gear lock screws take four M2; the 26-piece set covers M2-M4 plus 1/4in and 3/8in; M2.5 for cage side-lock hex socket screws, supplied as M2.5 in the MB2734 screw set; M3 for gear lock screws — four M3 on current gears (older gears take four M2); sets also include M2.5 hex socket screws for cage side locks.
- How long are the screws in SmallRig camera cages and rigs?
- None of the sources states a length. Remove one screw and measure it from under the head to the tip (overall for a countersunk head).
- 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 SmallRig camera cages and rigs?
- The source lists a Hex socket (Allen) drive. Standard M2 heads otherwise take PH0 (Phillips) or T6 (Torx), or 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.