Telescope metric thumb screw for telescope parts screw size
M3 · 8 mm long
If you are replacing a screw on Telescope metric thumb screw for telescope parts, the thread is M3, 8 mm long.
Where it is used: listing: 'Metric Thumb Screws M3 M4 Telescope Parts... Size: M3 x 8mm'.
Head and drive, as the source states them: thumb screw (knurled) head.
This entry is marked confirmed and comes from telescopescanada.ca.
M3 means a 3 mm nominal diameter with a 0.5 mm thread pitch. Imperial look-alike: #5-40 (3.18 mm) or #4-40 — neither interchanges with M3.
Telescope metric thumb screw for telescope 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 |
|---|---|---|---|---|---|---|
| M3 | 8 mm | 0.5 mm | Thumb screw (knurled) | not stated | Listing: 'Metric Thumb Screws M3 M4 Telescope Parts... Size: M3 x 8mm' | Confirmed |
Fitment records and sources
Listing: 'Metric Thumb Screws M3 M4 Telescope Parts... Size: M3 x 8mm'
pitch 0.5 mm · tap 2.5 mm · clearance 3.4 mm · PH1 / Torx T10
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 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: for thumb screw (knurled) screws, measure from under the head to the tip (countersunk heads are the exception: they 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 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
- Telescope thumbscrews are sold in a wide non-metric legacy range too (1/4-20, 8-32, 10-32 on many Meade/Celestron mounts), so metric M3/M4 fitment applies mainly to newer/international accessory ecosystems (SkyWatcher, generic 1.25" accessories) and should not be assumed universal.
- Intel's ATX and microATX specs never state a metric standoff thread; PC motherboard standoffs are usually imperial 6-32, and PC fan screws are commonly 6-32 self-tapping.
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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M3 x 8mm Phillips Wafer Head Screw for SLA Resin 3D Printer VAT Film - Single Replacement Black
$0.10 each · min. 50
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M3 x 8mm Phillips Flat Head Countersunk Machine Screws Zinc Silver 100-Pack for RC & 3D Printers
$9.99 -
M3 x 8mm Phillips Flat Head Countersunk Machine Screws Zinc Silver 10-Pack for RC & 3D Printers
$4.99
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Browse all 278 in Cameras & Optics →The same screw also fits
Devices whose records share a thread with Telescope metric thumb screw for telescope parts, closest length match first.
- Celestron C8 Schmidt-Cassegrain OTA secondary mirror collimation screws also M3 × 8 mm
- Camera cage shells (SmallRig-style) also M3 × 8 mm
- Airsoft red dot sight mounting screw set (Laylax/Quintes Sence) also M3 × 8 mm
- Universal Red Dot Pattern Mounting Plate (fits Vortex Viper, Burris Fast Fire 3, UTG Reflex Micro Dot, TruGlo Tru-Tec, Crimson Trace CTS-1250, Springfield Dragonfly) also M3 × 8 mm
- Wooden Camera 153200 SSD Guard (RED SCARLET) also M3 × 8 mm
- Meade LX200 Barlow / eyepiece retaining screw also M3 × 8 mm
- Gimbal / quick-release plate clamp also M3 × 8 mm
- Celestron collimation screws, C5/C6/C8 SCT optical tubes also M3 × 8 mm
Questions about Telescope metric thumb screw for telescope parts screws
- What size screw does Telescope metric thumb screw for telescope parts use?
- M3 × 8 mm for listing: 'Metric Thumb Screws M3 M4 Telescope Parts... Size: M3 x 8mm'.
- How long are the screws in Telescope metric thumb screw for telescope parts?
- 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 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 Telescope metric thumb screw for telescope parts?
- 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.
- Where can I buy replacement screws for Telescope metric thumb screw for telescope parts?
- TechSpareWarehouse (our own store) lists M3 x 8mm, which matches the length in the records above.