Celestron NexStar 8 eyepiece holder screw size
M4 · 12 mm long
The screws used on Celestron NexStar 8 eyepiece holder are M4, 12 mm long.
It is listed for eyepiece holder thumb screw, M4-0.7 round tip.
Head and drive, as the source states them: thumb screw (knurled) head.
This entry is marked confirmed and comes from scopestuff.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.
Celestron NexStar 8 eyepiece holder 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 | Thumb screw (knurled) | not stated | eyepiece holder thumb screw, M4-0.7 round tip | Confirmed |
Fitment records and sources
eyepiece holder thumb screw, M4-0.7 round tip
pitch 0.7 mm · tap 3.3 mm · clearance 4.5 mm · PH2 / Torx T20
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 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: for thumb screw (knurled) screws, measure from under the head to the tip (countersunk heads are the exception: they 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.
- M4 and 6-32 UNC share a nominal diameter with different pitch — a classic cross-thread in US-market kits.
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 Celestron NexStar 8 eyepiece holder, closest length match first.
- Gimbal stabilizer arm clamp also M4 × 12 mm
- Telescope eyepiece fixing set-screw also M4 × 12 mm
- 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
- Holosun 507k/407k screw, Glock 43X/48 MOS shim plate also M4 × 12 mm
Questions about Celestron NexStar 8 eyepiece holder screws
- What size screw does Celestron NexStar 8 eyepiece holder use?
- M4 × 12 mm for eyepiece holder thumb screw, M4-0.7 round tip.
- How long are the screws in Celestron NexStar 8 eyepiece holder?
- 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 Celestron NexStar 8 eyepiece holder?
- 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.