ZWO EFW filter wheel to ASI camera screw size
M2.5 · length not stated in the sources
ZWO EFW filter wheel to ASI camera takes M2.5 metric screws. None of the sources we found gives an exact length, so measure the original before you order.
The record covers filter wheel mounting screws (community-confirmed).
This entry is marked reported and comes from bbs.zwoastro.com.
For reference, M2.5 is 2.5 mm across the threads at 0.45 mm pitch. The imperial size people confuse it with: #3-48 / #4-40 (2.51 / 2.84 mm) — #4-40 is the common US stand-in and it will NOT thread in.
ZWO EFW filter wheel to ASI camera 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 | not stated | 0.45 mm | not stated | not stated | filter wheel mounting screws (community-confirmed) | Reported |
Fitment records and sources
M2.5reported
filter wheel mounting screws (community-confirmed)
pitch 0.45 mm · tap 2.05 mm · clearance 2.9 mm · PH1 / Torx T8
How to check the screw before you buy
- Do not confuse metric mounting screws with the 1/4-20 or 3/8-16 tripod threads that cameras and clamps also carry.
- 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: measure from under the head to the tip for pan, button, wafer and cap heads; countersunk (flat) heads are measured overall.
- 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
- 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.
- In dental implantology, M2.5 appears as an explicit, standardized internal screw thread for implant abutment/prosthetic screw retrieval and repair taps (confirmed via Nobel Biocare), distinct from generic 'dental screw' marketing claims that lack thread specification.
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Devices whose records share a thread with ZWO EFW filter wheel to ASI camera, closest length match first.
- Microscope objective turret also M2.5
- Wooden Camera Pocket Cage 168800 also M2.5
- Wooden Camera battery plate wedge (Blackmagic URSA Cine 12K/17K) also M2.5
- Kurokesu QR-PLATE-20 Arca-Swiss plate also M2.5
- Camera cages & rigs also M2.5
- Tripod head quick-release plate lock also M2.5
- SmallRig CCP2525 cage (Panasonic S5) also M2.5
- SmallRig CCP2646 cage (Lumix GH5/GH5 II/GH5S) also M2.5
Questions about ZWO EFW filter wheel to ASI camera screws
- What size screw does ZWO EFW filter wheel to ASI camera use?
- M2.5 for filter wheel mounting screws (community-confirmed).
- How long are the screws in ZWO EFW filter wheel to ASI camera?
- 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 M2.5 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 ZWO EFW filter wheel to ASI camera?
- 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.