Scope / rail mount base screws (metric) screw size
M4 · 10 mm long
Scope / rail mount base screws (metric) takes M4 metric screws, 10 mm long.
Where it is used: replacement rail-mount screws sold in metric M4 Torx, 10mm thread length.
Head and drive, as the source states them: Torx drive.
This entry is marked confirmed and comes from ant-supplies.uk.
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.
Scope / rail mount base screws (metric) 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 | 10 mm | 0.7 mm | not stated | Torx | Replacement rail-mount screws sold in metric M4 Torx, 10mm thread length | Confirmed |
Fitment records and sources
Replacement rail-mount screws sold in metric M4 Torx, 10mm thread length
pitch 0.7 mm · tap 3.3 mm · clearance 4.5 mm · PH2 / Torx T20
How to check the screw before you buy
- Where the manufacturer publishes a torque value, use a torque driver rather than feel.
- 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 10 mm. Going longer risks bottoming out or touching parts behind the hole; going shorter loses thread engagement.
- Driver: the source names a Torx drive. For comparison, standard M4 heads take PH2 (Phillips) or T20 (Torx), or a 3 mm hex key.
- 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
- There is no single standard Picatinny/rail screw size; makers use metric M3/M4 and imperial 6-48 or 8-40 interchangeably. Always measure the existing screw.
- Water heater elements use pipe threads (NPSM/NPT), not metric machine screws.
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.
More in Vehicles, Marine & Mobility
The same screw also fits
Devices whose records share a thread with Scope / rail mount base screws (metric), closest length match first.
- Motorcycle fairing panels also M4 × 10 mm
- Tyco/Advanced MX1 fire panel loop card kit also M4 × 10 mm
- Chainsaw air filter cover also M4 × 10 mm
- Drawer slide rails also M4 × 10 mm
- Innovative Control Systems Tunnel Master WBC car wash controller cabinet also M4 × 10 mm
- RV / camper cabinet hardware also M4 × 10 mm
- Car centre console and vent trim also M4 × 10 mm
- Car badge / emblem studs also M4 × 10 mm
Questions about Scope / rail mount base screws (metric) screws
- What size screw does Scope / rail mount base screws (metric) use?
- M4 × 10 mm for replacement rail-mount screws sold in metric M4 Torx, 10mm thread length.
- How long are the screws in Scope / rail mount base screws (metric)?
- The record gives 10 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 Scope / rail mount base screws (metric)?
- The source lists a Torx drive. Standard M4 heads otherwise take PH2 (Phillips) or T20 (Torx), or 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.