Thorlabs FW103/M motorized filter wheel screw size
M4 · length not stated in the sources
Thorlabs FW103/M motorized filter wheel takes M4 metric screws. None of the sources we found gives an exact length, so measure the original before you order.
The record covers metric variant listed with M4 taps for post or breadboard mounting.
This entry is marked confirmed and comes from govolition.com.
For reference, M4 is 4 mm across the threads at 0.7 mm pitch. The imperial size people confuse it with: #8-32 (4.17 mm) — the standard US PC/rack screw, close but not the same.
Thorlabs FW103/M motorized filter wheel 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 |
|---|---|---|---|---|---|---|
| M4 | not stated | 0.7 mm | not stated | not stated | Metric variant listed with M4 taps for post or breadboard mounting | Confirmed |
Fitment records and sources
Metric variant listed with M4 taps for post or breadboard mounting
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 M4 screw measures about 4 mm with calipers (usually a hair under). If yours measures noticeably more or less, it is a different thread.
- Pitch: 0.7 mm from one thread crest to the next (14.29 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 M4 heads take PH2 for Phillips and T20 for Torx, and a 3 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 M4 is about 2.0-3.0 N·m into metal threads and 0.8-1.4 N·m into plastic bosses; snug it up and stop.
Common mix-ups with M4
- Bopla SHR-Z boss screws and Hammond 1591XXF screws look metric but are self-tapping/imperial — don't substitute a machine screw into those bosses.
- Oster and Wahl clipper blade screws are often imperial #6-32, not metric - measure before assuming.
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Devices whose records share a thread with Thorlabs FW103/M motorized filter wheel, closest length match first.
- DJI RS series gimbals (RS 5, RS4 Pro, RS4, RS3 Mini/Pro/3, RS2, RSC2) also M4
- DJI RS 5 / RS 4 / RS 3 / RSC 2 gimbal camera mount also M4
- Thorlabs KM200CP/M kinematic mount for 2-inch optics also M4
- Main barrel / eyepiece extension tube holder set screws also M4
- Celestron NexStar 8 eyepiece holder set screws also M4
- SIG SAUER ROMEO-RS reflex sight, mounting to SIG Pro-cut slides / P365 slides with M4 mount holes also M4
- Newport M-SP-4 optical post, 101.6mm height, 12.7mm diameter also M4
- Celestron collimation screws, C8/C9.25/C11 SCT optical tubes also M4
Questions about Thorlabs FW103/M motorized filter wheel screws
- What size screw does Thorlabs FW103/M motorized filter wheel use?
- M4 for metric variant listed with M4 taps for post or breadboard mounting.
- How long are the screws in Thorlabs FW103/M motorized filter wheel?
- 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 M4 screw?
- 0.7 mm (coarse), which is the standard pitch for M4 machine screws; a 0.5 mm fine pitch exists but is uncommon. The tap drill is 3.3 mm and the normal clearance hole is 4.5 mm.
- What screwdriver do I need for Thorlabs FW103/M motorized filter wheel?
- The sources do not name the drive. For M4, Phillips heads normally take PH2 and Torx heads T20; socket heads take a 3 mm hex key.
- Can I use an imperial screw instead of M4?
- No. Imperial look-alike: #8-32 (4.17 mm) — the standard US PC/rack screw, close but not the same. Use a true M4 screw so it does not cross-thread or strip the hole.