Weaver scope base/ring mounts screw size
M4 · length not stated in the sources
The screws used on Weaver scope base/ring mounts are M4. None of the sources we found gives an exact length, so measure the original before you order.
Where it is used: scope base torque spec listed alongside legacy 6-48/8-40 imperial fasteners on some product lines (note: most Weaver hardware is imperial UNC).
This entry is marked reported and comes from weavermounts.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.
Weaver scope base/ring mounts 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 | not stated | not stated | Scope base torque spec listed alongside legacy 6-48/8-40 imperial fasteners on some product lines (note: most Weaver hardware is imperial UNC) | Reported |
Fitment records and sources
Scope base torque spec listed alongside legacy 6-48/8-40 imperial fasteners on some product lines (note: most Weaver hardware is imperial UNC)
pitch 0.7 mm · tap 3.3 mm · clearance 4.5 mm · PH2 / Torx T20
How to check the screw before you buy
- Scope and accessory mounts often publish a torque value; tighten to it in a cross pattern.
- 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.
- 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
- Most HVAC chassis hardware in US-market units is imperial; metric shows up mainly on European-made components.
- 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.
More in Sports, Outdoors & Optics Mounts
The same screw also fits
Devices whose records share a thread with Weaver scope base/ring mounts, closest length match first.
- Heart rate chest strap buckle also M4
- Fuge EVOLVE ski binding mounting jig also M4
- Fishing reel side plates also M4
- Archery/bow accessory set screws (generic component, not confirmed as sight-specific) also M4
- ISMS scope mount (Ideal Scope Mounting System) also M4
- Carbide3D Shapeoko 5 Pro CNC router also M4
- Elesa NT-HD-SST hygienic sealed screw knob also M4
- ABB ACS880-87CC wind turbine converter (nacelle power converter hardware manual) also M4
Questions about Weaver scope base/ring mounts screws
- What size screw does Weaver scope base/ring mounts use?
- M4 for scope base torque spec listed alongside legacy 6-48/8-40 imperial fasteners on some product lines (note: most Weaver hardware is imperial UNC).
- How long are the screws in Weaver scope base/ring mounts?
- 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 Weaver scope base/ring mounts?
- 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.