Sig Sauer ROMEO1 Pro mounting screw screw size
M4 · 8.5 mm long
If you are replacing a screw on Sig Sauer ROMEO1 Pro mounting screw, the thread is M4, 8.5 mm long.
Where it is used: SHCS M4 x 0.7 x 8.5mm per vendor writeup, not the Sig manual.
Head and drive, as the source states them: socket cap head and Hex socket (Allen) drive.
This entry is marked likely and comes from shuntool.com.
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.
Sig Sauer ROMEO1 Pro mounting 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 | 8.5 mm | 0.7 mm | Socket cap | Hex socket (Allen) | SHCS M4 x 0.7 x 8.5mm per vendor writeup, not the Sig manual | Likely |
Fitment records and sources
SHCS M4 x 0.7 x 8.5mm per vendor writeup, not the Sig manual
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 socket cap screws, measure from under the head to the tip (countersunk heads are the exception: they are measured overall).
- The record states 8.5 mm. Going longer risks bottoming out or touching parts behind the hole; going shorter loses thread engagement.
- Driver: the source names a Hex socket (Allen) 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
- M4 and 6-32 UNC share a nominal diameter with different pitch — a classic cross-thread in US-market kits.
More in Cameras & Optics
1.25" eyepiece/diagonal/SCT visual back thumb screwAimpoint Comp M4 / M4s LRP & TNP mountAimpoint Micro T-1/T-2/H-1/H-2 standard mountAimpoint Micro T-1/T-2/H-1/H-2 standard mount screwAimpoint SM-2001/2007 Micro T1/T2 mountAirsoft red dot sight mounting screw set (Laylax/Quintes Sence)Airsoft/firearm red-dot sight optic mounting screws (Vortex Viper, Swampfox patterns)Alpine and touring ski bindings (Binding Freedom inserts)Arca-style quick-release plateARRI plate for Sony VENICE 1/2Artesky 340mm Vixen Dovetail BarAstromania finder scope dovetail base
Browse all 278 in Cameras & Optics →The same screw also fits
Devices whose records share a thread with Sig Sauer ROMEO1 Pro mounting screw, closest length match first.
- Underwater camera housing latch and port also M4 × 8.5 mm
- Tilta TA-RF-LPL adapter ring support (RED KOMODO cage) also M4 × 8.5 mm
- Wooden Camera UMB-1 Universal Mattebox (Base/Clamp On/Swing Away/Pro) also M4 × 8.5 mm
- Telescope finder-scope shoe / base (TS-Optics) also M4 × 8.5 mm
- Celestron collimation screws, C8/C9.25/C11 SCT optical tubes also M4 × 8.5 mm
- DJI RS upper quick-release plate also M4 × 8.5 mm
- Diebold Opteva ATM cassette screw also M4 × 8.5 mm
- HP Color LaserJet 8500 2000-sheet input unit also M4 × 8.5 mm
Questions about Sig Sauer ROMEO1 Pro mounting screw screws
- What size screw does Sig Sauer ROMEO1 Pro mounting screw use?
- M4 × 8.5 mm for SHCS M4 x 0.7 x 8.5mm per vendor writeup, not the Sig manual.
- How long are the screws in Sig Sauer ROMEO1 Pro mounting screw?
- The record gives 8.5 mm. Measure the original from under the head (overall for a countersunk head) to confirm before ordering.
- What is the thread pitch of an 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 Sig Sauer ROMEO1 Pro mounting screw?
- The source lists a Hex socket (Allen) 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.