Telescope eyepiece fixing set-screw screw size
M4 · 12 mm long
Our records put Telescope eyepiece fixing set-screw on M4 screws, 12 mm long.
Where it is used: set-screw explicitly listed as M4x12 for eyepiece fixing in eyepiece holders/focusers.
This entry is marked confirmed and comes from tavcso.hu.
M4 means a 4 mm nominal diameter with a 0.7 mm thread pitch. Imperial look-alike: #8-32 (4.17 mm) — the standard US PC/rack screw, close but not the same.
Telescope eyepiece fixing set-screw 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 | 12 mm | 0.7 mm | not stated | not stated | Set-screw explicitly listed as M4x12 for eyepiece fixing in eyepiece holders/focusers | Confirmed |
Fitment records and sources
Set-screw explicitly listed as M4x12 for eyepiece fixing in eyepiece holders/focusers
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.
- The record states 12 mm. Going longer risks bottoming out or touching parts behind the hole; going shorter loses thread engagement.
- 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
- Not all telescope/finder hardware is metric — Celestron Edge/NexStar SE finder-shoe and dovetail screws are reported as 8/32 (imperial UNC), so metric M4/M5 fitments cannot be assumed across all Celestron products; must check per accessory/vintage.
- Festo sensor brackets are named after the sensor interface (DASP-M4-...), but the bracket's own fixing screws are often a different size (M5/M6/M8).
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 Telescope eyepiece fixing set-screw, closest length match first.
- Wimberley AP-609 lens foot plate also M4 × 12 mm
- Christie HS / Jazz Series UST lens bracket also M4 × 12 mm
- Celestron NexStar 8 eyepiece holder set screws also M4 × 12 mm
- SIG SAUER ROMEO-RS reflex sight, mounting to SIG Pro-cut slides / P365 slides with M4 mount holes also M4 × 12 mm
- Telescope finder-scope shoe / base (TS-Optics) also M4 × 12 mm
- Celestron NexStar 8 eyepiece holder also M4 × 12 mm
- Gimbal stabilizer arm clamp also M4 × 12 mm
- Underwater camera housing latch and port also M4 × 12 mm
Questions about Telescope eyepiece fixing set-screw screws
- What size screw does Telescope eyepiece fixing set-screw use?
- M4 × 12 mm for set-screw explicitly listed as M4x12 for eyepiece fixing in eyepiece holders/focusers.
- How long are the screws in Telescope eyepiece fixing set-screw?
- The record gives 12 mm. Measure the original from under the head (overall for a countersunk head) to confirm before ordering.
- 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 Telescope eyepiece fixing set-screw?
- 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.