Optic/scope ring mounting screw manufactured to engineering drawing (fastener supplier drawing, generic optics mount hardware) screw size
M4 · length not stated in the sources
If you are replacing a screw on Optic/scope ring mounting screw manufactured to engineering drawing (fastener supplier drawing, generic optics mount hardware), the thread is M4. None of the sources we found gives an exact length, so measure the original before you order.
The record covers fastener manufacturer engineering drawing for a screw explicitly dimensions the thread as "M4X0.7", used on an optics-mount tapped-hole assembly with a nylon-tipped set screw "for securing of mounted optic".
Head and drive, as the source states them: set screw (headless) head.
This entry is marked reported and comes from omtools-russia.ru.
An M4 screw is 4 mm in diameter with a 0.7 mm pitch, tapped with a 3.3 mm drill; imperial look-alike: #8-32 (4.17 mm) — the standard US PC/rack screw, close but not the same.
Optic/scope ring mounting screw manufactured to engineering drawing (fastener supplier drawing, generic optics mount hardware) 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 | Set screw (headless) | not stated | Fastener manufacturer engineering drawing for a screw explicitly dimensions the thread as "M4X0.7", used on an optics-mount tapped-hole assembly with a nylon-tipped set screw "for securing of mounted optic"thread-locking patch | Reported |
Fitment records and sources
Fastener manufacturer engineering drawing for a screw explicitly dimensions the thread as "M4X0.7", used on an optics-mount tapped-hole assembly with a nylon-tipped set screw "for securing of mounted optic"
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 set screw (headless) screws, measure from under the head to the tip (countersunk heads are the exception: they 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
- 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.
- Most HVAC chassis hardware in US-market units is imperial; metric shows up mainly on European-made components.
More in Cameras & Optics
The same screw also fits
Devices whose records share a thread with Optic/scope ring mounting screw manufactured to engineering drawing (fastener supplier drawing, generic optics mount hardware), closest length match first.
- Celestron NexStar 8 eyepiece holder also M4
- Thorlabs ELL21/M rotation mount also M4
- Edmund Optics metric post kit also M4
- Gimbal stabilizer arm clamp also M4
- Newport M-SP-2 optical post also M4
- i-PRO / Panasonic WV-QWL100 camera mount bracket also M4
- Vivotek IT9360-H / IT9380-H dome camera also M4
- OpenFlexure Delta Stage frame also M4
Questions about Optic/scope ring mounting screw manufactured to engineering drawing (fastener supplier drawing, generic optics mount hardware) screws
- What size screw does Optic/scope ring mounting screw manufactured to engineering drawing (fastener supplier drawing, generic optics mount hardware) use?
- M4 for fastener manufacturer engineering drawing for a screw explicitly dimensions the thread as "M4X0.7", used on an optics-mount tapped-hole assembly with a nylon-tipped set screw "for securing of mounted optic".
- How long are the screws in Optic/scope ring mounting screw manufactured to engineering drawing (fastener supplier drawing, generic optics mount hardware)?
- 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 Optic/scope ring mounting screw manufactured to engineering drawing (fastener supplier drawing, generic optics mount hardware)?
- 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.