Leica M-series stereo microscopes (M165/M205) screw size
M3 / M4 · length not stated in the sources
Leica M-series stereo microscopes (M165/M205) takes M3 and M4 metric screws. None of the sources we found gives an exact length, so measure the original before you order.
There are 2 separate fitment records for it, including 2x M3 screws release the stage holder during mechanical-stage removal (M3) and 2x M4 screws remove the sleeve from the mechanical stage (M4).
2 of the 2 records are marked confirmed, drawn from 1 source (leica.manymanuals.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.
Leica M-series stereo microscopes (M165/M205) 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 | not stated | 0.5 mm | not stated | not stated | 2x M3 screws release the stage holder during mechanical-stage removal | Confirmed |
| M4 | not stated | 0.7 mm | not stated | not stated | 2x M4 screws remove the sleeve from the mechanical stage | Confirmed |
Fitment records and sources
2x M3 screws release the stage holder during mechanical-stage removal
pitch 0.5 mm · tap 2.5 mm · clearance 3.4 mm · PH1 / Torx T10
2x M4 screws remove the sleeve from the mechanical stage
pitch 0.7 mm · tap 3.3 mm · clearance 4.5 mm · PH2 / Torx T20
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 M3 screw measures about 3 mm with calipers (usually a hair under). This device also uses M4, so measure each screw rather than assuming they match.
- 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: 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 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 / M4
- Sonos speakers mix lengths within one unit — M3 for driver housings, M2.5 at the control panel. Keep them sorted during teardown.
- M3 (3.0mm, 0.5mm pitch) is not #6-32 UNC (~3.5mm) — they look identical and cross-thread, the single most common PC-building mistake.
- M4 and 6-32 UNC share a nominal diameter with different pitch — a classic cross-thread in US-market kits.
More in Cameras & Optics
The same screw also fits
Devices whose records share a thread with Leica M-series stereo microscopes (M165/M205), closest length match first.
- Holosun SCS-MOS optic mounting screw (Glock) also M3
- Vortex Viper enclosed micro red dot on Beretta 1301 Comp / Browning Maxus II also M4
- ARRI plate for Sony VENICE 1/2 also M4
- Thorlabs CCM5-BS017/M 16mm cage cube beamsplitter also M4
- Explore Scientific / Meade style finder shoe also M4
- Partizan / Pilotix PT10 V3 FPV frame also M3
- Wimberley AP-609 lens foot plate also M4
- ScopeStuff nylon thumbscrew kit also M3
Questions about Leica M-series stereo microscopes (M165/M205) screws
- What size screw does Leica M-series stereo microscopes (M165/M205) use?
- M3 for 2x M3 screws release the stage holder during mechanical-stage removal; M4 for 2x M4 screws remove the sleeve from the mechanical stage.
- How long are the screws in Leica M-series stereo microscopes (M165/M205)?
- 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 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 Leica M-series stereo microscopes (M165/M205)?
- 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.