Holosun SCS mounting screw (Walther PDP) screw size
M3 · 6.5 mm long
Our records put Holosun SCS mounting screw (Walther PDP) on M3 screws, 6.5 mm long.
The record covers M3 x 0.5 x 6.5mm.
This entry is marked confirmed and comes from battlewerx.com.
For reference, M3 is 3 mm across the threads at 0.5 mm pitch. The imperial size people confuse it with: #5-40 (3.18 mm) or #4-40 — neither interchanges with M3.
Holosun SCS mounting screw (Walther PDP) 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 |
|---|---|---|---|---|---|---|
| M3 | 6.5 mm | 0.5 mm | not stated | not stated | M3 x 0.5 x 6.5mm | Confirmed |
Fitment records and sources
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 M3 screw measures about 3 mm with calipers (usually a hair under). If yours measures noticeably more or less, it is a different thread.
- Pitch: 0.5 mm from one thread crest to the next (20 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 6.5 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 M3 heads take PH1 for Phillips and T10 for Torx, and a 2.5 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 M3 is about 80-130 N·cm into metal threads and 35-60 N·cm into plastic bosses; snug it up and stop.
Common mix-ups with M3
- M3 (3.0mm, 0.5mm pitch) is not #6-32 UNC (~3.5mm) — they look identical and cross-thread, the single most common PC-building mistake.
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Devices whose records share a thread with Holosun SCS mounting screw (Walther PDP), closest length match first.
- Meade LX200 Barlow / eyepiece retaining screw also M3 × 6.5 mm
- Gimbal / quick-release plate clamp also M3 × 6.5 mm
- Camera cage shells (SmallRig-style) also M3 × 6.5 mm
- Microscope objective turret and stage also M3 × 6.5 mm
- Olympus BH-2 microscope frame also M3 × 6.5 mm
- Wimberley AP-640 replacement lens foot also M3 × 6.5 mm
- Refrigerator light cover and shelf clips also M3 × 6.5 mm
- Vintage camera / electronics faceplates also M3 × 6.5 mm
Questions about Holosun SCS mounting screw (Walther PDP) screws
- What size screw does Holosun SCS mounting screw (Walther PDP) use?
- M3 × 6.5 mm for M3 x 0.5 x 6.5mm.
- How long are the screws in Holosun SCS mounting screw (Walther PDP)?
- The record gives 6.5 mm. Measure the original from under the head (overall for a countersunk head) to confirm before ordering.
- What is the thread pitch of an M3 screw?
- 0.5 mm (coarse), which is the standard pitch for M3 machine screws; a 0.35 mm fine pitch exists but is uncommon. The tap drill is 2.5 mm and the normal clearance hole is 3.4 mm.
- What screwdriver do I need for Holosun SCS mounting screw (Walther PDP)?
- The sources do not name the drive. For M3, Phillips heads normally take PH1 and Torx heads T10; socket heads take a 2.5 mm hex key.
- Can I use an imperial screw instead of M3?
- No. Imperial look-alike: #5-40 (3.18 mm) or #4-40 — neither interchanges with M3. Use a true M3 screw so it does not cross-thread or strip the hole.