RC servo horn retaining screw (Hitec/Futaba style) screw size
M2.5 · 8 mm long
RC servo horn retaining screw (Hitec/Futaba style) takes M2.5 metric screws, 8 mm long.
Where it is used: M2.5-0.45 x 8mm screw retains the servo horn/arm.
This entry is marked confirmed and comes from andymark.com.
For reference, M2.5 is 2.5 mm across the threads at 0.45 mm pitch. The imperial size people confuse it with: #3-48 / #4-40 (2.51 / 2.84 mm) — #4-40 is the common US stand-in and it will NOT thread in.
RC servo horn retaining screw (Hitec/Futaba style) 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 |
|---|---|---|---|---|---|---|
| M2.5 | 8 mm | 0.45 mm | not stated | not stated | M2.5-0.45 x 8mm screw retains the servo horn/arm | Confirmed |
Fitment records and sources
M2.5-0.45 x 8mm screw retains the servo horn/arm
pitch 0.45 mm · tap 2.05 mm · clearance 2.9 mm · PH1 / Torx T8
How to check the screw before you buy
- Frame and motor screws must not reach the motor windings; check the length against the motor's mounting depth.
- Diameter: across the threads an M2.5 screw measures about 2.5 mm with calipers (usually a hair under). If yours measures noticeably more or less, it is a different thread.
- Pitch: 0.45 mm from one thread crest to the next (22.22 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 8 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 M2.5 heads take PH1 for Phillips and T8 for Torx, and a 2 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 M2.5 is about 45-70 N·cm into metal threads and 20-35 N·cm into plastic bosses; snug it up and stop.
Common mix-ups with M2.5
- M2.5 pitch is 0.45mm vs M3's 0.5mm and M2's 0.4mm — forcing the wrong one strips plastic bosses instantly.
- M2.5 and M3 look the same to the naked eye — you need calipers on the shank to tell them apart.
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.
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M2.5 x 8mm Screws for Raspberry Pi 5 Case and PoE HAT 10-Pack Black
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25x M2.5 x 8mm Phillips Screws for Acer Nitro 5 LCD Hinge Assembly
$5.99 -
M2.5 x 8mm Black Wafer Head Screws for Lenovo ThinkPad X131e Chromebook Palmrest Replacement – 10-Pack Black
$4.99Choose size
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Devices whose records share a thread with RC servo horn retaining screw (Hitec/Futaba style), closest length match first.
- Axial SCX10 III RC crawler, countersunk and cap screws also M2.5 × 8 mm
- Antique wall clock pendulum brackets also M2.5 × 8 mm
- Hitec / Futaba servo horn retaining screw also M2.5 × 8 mm
- PowerVision PowerRay underwater drone also M2.5 × 8 mm
- Sewing machine needle plate also M2.5 × 8 mm
- Raspberry Pi (Model B+ through Pi 4/Pi 5 form factor boards) also M2.5 × 8 mm
- Model aircraft control horns also M2.5 × 8 mm
- Drone remote controller internals also M2.5 × 8 mm
Questions about RC servo horn retaining screw (Hitec/Futaba style) screws
- What size screw does RC servo horn retaining screw (Hitec/Futaba style) use?
- M2.5 × 8 mm for M2.5-0.45 x 8mm screw retains the servo horn/arm.
- How long are the screws in RC servo horn retaining screw (Hitec/Futaba style)?
- The record gives 8 mm. Measure the original from under the head (overall for a countersunk head) to confirm before ordering.
- What is the thread pitch of an M2.5 screw?
- 0.45 mm (coarse), which is the standard pitch for M2.5 machine screws; a 0.35 mm fine pitch exists but is uncommon. The tap drill is 2.05 mm and the normal clearance hole is 2.9 mm.
- What screwdriver do I need for RC servo horn retaining screw (Hitec/Futaba style)?
- The sources do not name the drive. For M2.5, Phillips heads normally take PH1 and Torx heads T8; socket heads take a 2 mm hex key.
- Can I use an imperial screw instead of M2.5?
- No. Imperial look-alike: #3-48 / #4-40 (2.51 / 2.84 mm) — #4-40 is the common US stand-in and it will NOT thread in. Use a true M2.5 screw so it does not cross-thread or strip the hole.
- Where can I buy replacement screws for RC servo horn retaining screw (Hitec/Futaba style)?
- TechSpareWarehouse (our own store) lists M2.5 x 8mm, which matches the length in the records above.