Meccano boxed sets (modern metric era) and compatible parts screw size
M4 · 5 to 25 mm long
If you are replacing a screw on Meccano boxed sets (modern metric era) and compatible parts, the thread is M4 in lengths from 5 to 25 mm.
Where it is used: standard nut-and-bolt system thread for modern Meccano.
This entry is marked confirmed and comes from meccanoandcomp.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.
Meccano boxed sets (modern metric era) and compatible parts 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 | 5–25 mm | 0.7 mm | not stated | not stated | standard nut-and-bolt system thread for modern Meccano | Confirmed |
Fitment records and sources
standard nut-and-bolt system thread for modern Meccano
pitch 0.7 mm · tap 3.3 mm · clearance 4.5 mm · PH2 / Torx T20
How to check the screw before you buy
- Vibration loosens small screws on drones and RC models, so builders commonly add a drop of medium (blue) threadlocker on metal-to-metal joints — never on plastic.
- 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 records span 5–25 mm, which means different positions take different lengths — match each hole to its own screw.
- 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
- goBILDA is metric M4; the older Actobotics/ServoCity system it resembles is imperial 6-32. The parts look alike and will strip each other.
- Pinball machines are historically imperial (UNC/UNF). Metric M4 shows up mainly in specific parts like cooling fans or in European rebuilds.
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 Drones, RC & Gimbals
The same screw also fits
Devices whose records share a thread with Meccano boxed sets (modern metric era) and compatible parts, closest length match first.
- GoPro-style action cam mount on FPV frames also M4 × 15–20 mm
- DJI Agras Agras T25/T50 spray drone screw with pad also M4 × 12 mm
- Berkel 330M Slicer base/transmission fastener (short) also M4 × 6 mm
- European mortise lock faceplates also M4 × 10–20 mm
- Padlock and safe internals also M4 × 6–12 mm
- goBILDA metric building system also M4 × 6–25 mm
- Maytronics Dolphin robotic pool cleaner (Ad-series/other Dolphin models) also M4 × 14 mm
- Singer / Bernette / EverSewn / Necchi sewing machines also M4 × 6 mm
Questions about Meccano boxed sets (modern metric era) and compatible parts screws
- What size screw does Meccano boxed sets (modern metric era) and compatible parts use?
- M4 × 5–25 mm for standard nut-and-bolt system thread for modern Meccano.
- How long are the screws in Meccano boxed sets (modern metric era) and compatible parts?
- The records range from 5 to 25 mm depending on the position, so match each screw to its own hole.
- 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 Meccano boxed sets (modern metric era) and compatible parts?
- 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.