Microscope objective turret screw size
M2.5 · 4 to 8 mm long
The screws used on Microscope objective turret are M2.5 in lengths from 4 to 8 mm.
It is listed for the nosepiece / objective retaining collar on lab microscopes.
This entry is marked reported and comes from alibaba.com.
M2.5 means a 2.5 mm nominal diameter with a 0.45 mm thread pitch. 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.
Microscope objective turret 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 | 4–8 mm | 0.45 mm | not stated | not stated | the nosepiece / objective retaining collar on lab microscopes | Reported |
Fitment records and sources
the nosepiece / objective retaining collar on lab microscopes
pitch 0.45 mm · tap 2.05 mm · clearance 2.9 mm · PH1 / Torx T8
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 M2.5 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.
- The records span 4–8 mm, which means different positions take different lengths — match each hole to its own screw.
- 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.
- M2.5 and M3 look the same to the naked eye — you need calipers on the shank to tell them apart.
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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Devices whose records share a thread with Microscope objective turret, closest length match first.
- Kurokesu QR-PLATE-20 Arca-Swiss plate also M2.5 × 5 mm
- Camera cages & rigs also M2.5 × 4–8 mm
- Raspberry Pi camera module mounts also M2.5 × 4–8 mm
- Tripod head quick-release plate lock also M2.5 × 8 mm
- Camera lens mount flange also M2.5 × 4–6 mm
- Camera hot shoe base plate also M2.5 × 4–5 mm
- OpenFlexure Delta Stage v1.1.0 motor mounts also M2.5 × 8 mm
- HP Compaq TC1000 also M2.5 × 5 mm
Questions about Microscope objective turret screws
- What size screw does Microscope objective turret use?
- M2.5 × 4–8 mm for the nosepiece / objective retaining collar on lab microscopes.
- How long are the screws in Microscope objective turret?
- The records range from 4 to 8 mm depending on the position, so match each screw to its own hole.
- 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 Microscope objective turret?
- 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.
- Where can I buy replacement screws for Microscope objective turret?
- TechSpareWarehouse (our own store) lists M2.5 x 4mm, M2.5 x 5mm and M2.5 x 6mm, which match lengths in the records above.