---
title: "M2.5 Micro Small Countersunk Phillips Machine Screws Dimensions"
description: "M2.5 Micro Small Countersunk Phillips Machine Screws: head diameter 3.8 mm, head height 0.8 mm, coarse thread pitch 0.45 mm."
url: https://engineeringhardware.com/guide/size/m2-5-micro-small-countersunk-phillips-machine-screws/
source: Engineering Hardware & Fasteners
---

# M2.5 Micro Small Countersunk Phillips Machine Screws Dimensions

Screws · Trade series (micro machine screws)

Controlling dimensions to Trade series (micro machine screws), with clearance hole and tapping drill, spanner or drive size and tightening torque.

M2.5 Micro Small Countersunk Phillips Machine Screws dimensions to Trade series (micro machine screws): head diameter 3.8 mm, head height 0.8 mm, coarse thread pitch 0.45 mm, clearance hole (ISO 273 medium) 2.9 mm. Tighten to approximately 0.7 Nm at property class 8.8 in a dry, as-supplied condition.

- **Head diameter:** 3.8 mm
- **Head height:** 0.8 mm
- **Coarse thread pitch:** 0.45 mm
- **Clearance hole (ISO 273 medium):** 2.9 mm
- **Tightening torque (class 8.8):** 0.7 Nm

Figures are nominal values from the governing standard. Confirm against the tolerance class for your application before machining or ordering.

![M2.5 Micro Small Countersunk Phillips Machine Screws Dimensions reference image](https://engineeringhardware.com/wp-content/uploads/2026/09/Micro-Small-Countersunk-Phillips-Machine-Screws.webp)

The M2.5 size of Micro Small Countersunk Phillips Machine Screws is dimensioned by Trade series (micro machine screws). The tables below give the dimensional row from the standard, the drill and spanner sizes that go with it, and the assembly torque per property class. The technical drawing on this page redraws to the exact values selected.

## M2.5 Dimensional Row (Trade series (micro machine screws))

| Thread size | Head diameter (mm) | Head height (mm) | Typical length range (mm) | Countersink angle (deg) | Material options |
| --- | --- | --- | --- | --- | --- |
| M2.5 | 3.8 | 0.80 | 2~20 | 90 | steel / A2 or 316 stainless / brass |

## Spanner & Drive for M2.5 Micro Small Countersunk Phillips Machine Screws

The hex socket for M2.5 Micro Small Countersunk Phillips Machine Screws is shown in the spec table — use the matching Allen / hex key (an ISO 2936 hex key set covers the full range). For a one-off, a T-handle key and a calibrated arm will do. For a batch, the only way to get the same preload twice is a torque-controlled driver.

## Hole Sizes for M2.5

| Coarse-thread pitch (ISO 724) | 0.45 mm |
| --- | --- |
| Through-hole / clearance (ISO 273 medium) | 2.9 mm |
| Tapping drill, coarse thread | 2.05 mm |

## Tightening Torque for M2.5

| Class 8.8 (dry, ~µ 0.125) | ≈ 0.7 Nm |
| --- | --- |
| Class 10.9 (dry, ~µ 0.125) | ≈ Nm |
| Class 12.9 (dry, ~µ 0.125) | ≈ 1.2 Nm |

Indicative dry-joint values. Lubrication can lower the required torque by 15–25%. Always confirm against the joint design, especially when going up a strength class.

## Proof Load & Strength for M2.5

| Tensile stress area As (ISO 724) | 3.4 mm² |
| --- | --- |
| Proof load, class 8.8 | 2 kN |
| Proof load, class 12.9 | 3.3 kN |
| Min. ultimate tensile load, class 8.8 | 2.7 kN |

Proof load = tensile stress area × the proof stress Sp of the class, per ISO 898-1 — Sp is a lower figure than the yield stress Rp0.2 and the two are not interchangeable. The stress area is computed from this size's own diameter and pitch, so a fine-pitch designation gives the fine-pitch figure. Design the joint so the working preload stays below the proof load of the class selected.

## M2.5 Micro Small Countersunk Phillips Machine Screws Weight

A steel M2.5 micro small countersunk phillips machine screws at the listed 220 mm length weighs approximately 8.5 g each — about 8.5 kg per 1,000 pieces. Stainless A2/A4 weighs roughly the same (density 7.9–8.0 g/cm³).

Actual weight varies slightly with head form, thread and finish; use this figure for freight estimation only.

## Installation Tips for M2.5 Micro Small Countersunk Phillips Machine Screws

- Use a quality Allen key fully seated in the socket — partial engagement is the most common cause of stripped sockets at this size.
- For countersunk and button-head variants, chamfer the through-hole to seat the head flush without preloading the head/shank fillet.
- At M2.5 the joint is sensitive to over-torque — use a torque-limiting driver and check the head doesn't bury into a softer counterpart.

## Mating Parts for M2.5

For M2.5, pair with a M2.5 hex nut (ISO 4032 / DIN 934) and, where used, a M2.5 flat washer (ISO 7089 / DIN 125A) under the head and under the nut.

Custom manufacturing · Made to drawing

## Need micro small countersunk phillips machine screws in a size this table does not list?

This page covers M2.5 micro small countersunk phillips machine screws. Thread size and pitch, length, property class, drive form, head geometry and head marking are all specifiable — the standard part is where it starts, not where it stops. Made by cold heading or warm forging.

Minimum order from 2,000 pieces; samples within 7 days of drawing approval.

[Custom screw manufacturing](https://engineeringhardware.com/custom/screws/)[Send a drawing](https://engineeringhardware.com/custom/screws/#rfq)

## Technical Drawing

Dimensioned line drawing of M2.5 Micro Small Countersunk Phillips Machine Screws to Trade series (micro machine screws). Side view and top view, drawn to the dimensions in the table below and redrawn for any size selected.

- **Head diameter (mm):** 3.8
- **Head height (mm):** 0.80
- **Typical length range (mm):** 2~20
- **Countersink angle (deg):** 90
- **Material options:** steel / A2 or 316 stainless / brass

## Dimensions & Specifications (Trade series (micro machine screws))

| Thread size | Head diameter (mm) | Head height (mm) | Typical length range (mm) | Countersink angle (deg) | Material options |
| --- | --- | --- | --- | --- | --- |
| M1.4 | 2.0 | 0.45 | 2~20 | 90 | steel / A2 or 316 stainless / brass |
| M1.6 | 2.4 | 0.50 | 2~20 | 90 | steel / A2 or 316 stainless / brass |
| M1.7 | 2.5 | 0.50 | 2~20 | 90 | steel / A2 or 316 stainless / brass |
| M2.0 | 3.0 | 0.60 | 2~20 | 90 | steel / A2 or 316 stainless / brass |
| M2.3 | 3.5 | 0.70 | 2~20 | 90 | steel / A2 or 316 stainless / brass |
| M2.5 | 3.8 | 0.80 | 2~20 | 90 | steel / A2 or 316 stainless / brass |
| M2.6 | 4.0 | 0.80 | 2~20 | 90 | steel / A2 or 316 stainless / brass |

Product catalog

## Related Micro Countersunk Screws products

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Countersunk & Flat-Head Machine Screws

### [M2-M20 65mm M8 300mm 5/16 1 21/64 Inch Length M30-3.5 Thread Size Logo Snap Fasteners Wing Screw China Factories](https://engineeringhardware.com/product/m2-m20-65mm-m8-300mm-5-16-1-21-64-inch-length-m30-3-5-thread-size-logo-snap/)

Countersunk Head · DIN, GB, ANSI, BSW, JIS, GOST

**US$0.012 – 0.12**MOQ 1,000 pieces

[![China Yellow Zinc Plated Ring Nails/Countersunk Head Ring Groove Nails/Stainless Steel Floor Nail/ Lay Silk Twist Nails/Pallet Nail All Kinds of Models](https://img.engineeringhardware.com/China-Yellow-Zinc-Plated-Ring-Nails-Countersunk-Head-Ring-Groove-Nails-Stainless-Steel-Floor-Nail-Lay-Silk-Twist-Nails-Pallet-Nail-All-Kinds-of-Models.webp)](https://engineeringhardware.com/product/china-yellow-zinc-plated-ring-nails-countersunk-head-ring-groove-nails-stainless/)

Countersunk & Flat-Head Machine Screws

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Common Nail · ANSI, DIN, GB, ISO, JIS

**US$0.012 – 0.12**MOQ 100 pieces

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Countersunk & Flat-Head Machine Screws

### [Customizable Flat Head Socket Screws Free Sample Provided OEM ODM Fastener Manufacturer](https://engineeringhardware.com/product/customizable-flat-head-socket-screws-free-sample-provided-oem-odm-fastener/)

Pan Head · DIN, GB, ANSI, BSW, JIS, GOST

**US$0.0001 – 0.0005**MOQ 500 pieces

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Countersunk & Flat-Head Machine Screws

### [High-Quality 4.8 Grade Carbon Steel Slotted Head Screws](https://engineeringhardware.com/product/high-quality-4-8-grade-carbon-steel-slotted-head-screws/)

Slotted Countersunk Head Machine Screw · DIN963, ISO2009, GB68, Uni610…

**US$0.0216 – 0.06**MOQ 1,000 pieces

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Countersunk & Flat-Head Machine Screws

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Countersunk Head · Steel

**US$0.006**MOQ 100,000 pieces

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Countersunk & Flat-Head Machine Screws

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Compound Slot · DIN

**US$0.012 – 0.036**MOQ 5,000 pieces

[View all Countersunk & Flat-Head Machine Screws →](https://engineeringhardware.com/fastener-products/screws/countersunk-flat-head-machine-screws/) [Full product catalog](https://engineeringhardware.com/products/)

## Materials & Grades

Select a material class to see the grades we supply it in. Each designation is listed with its ISO/EN, AISI/SAE, JIS and GB equivalents.

Stainless Steel38 Carbon Steel66 Alloy Steel41 Bearing Steel5 Spring Steel25 Aluminum and Aluminum Alloys21 Brass17 Bronze11 Copper8 Titanium and Titanium Alloys18 Nickel and Nickel Alloys22 Iron-Nickel and High-Temperature Alloys10 Tool Steel and Specialty Hardened Steel9 Structural and Construction Steel9

### Stainless Steel

#### Austenitic Stainless Steel

- A1 AISI 303 · SAE 303 · SUS303 · EN 1.4305 · X8CrNiS18-9
- A2 AISI 304 · SAE 304 · SUS304 · EN 1.4301 · X5CrNi18-10 · 06Cr19Ni10
- 304L AISI 304L · SUS304L · EN 1.4307 · X2CrNi18-9 · 022Cr19Ni10
- 302 AISI 302 · SUS302 · EN 1.4310
- 305 AISI 305 · SUS305 · EN 1.4303
- A4 AISI 316 · SAE 316 · SUS316 · EN 1.4401 · X5CrNiMo17-12-2 · 06Cr17Ni12Mo2
- 316L AISI 316L · SUS316L · EN 1.4404 · X2CrNiMo17-12-2 · 022Cr17Ni12Mo2
- 321 AISI 321 · SUS321 · EN 1.4541 · X6CrNiTi18-10
- 310 / 310S AISI 310 · AISI 310S · SUS310S · EN 1.4845
- 302HQ AISI 302HQ
- A3
- A5
- 347 AISI 347 · SUS347 · EN 1.4550 · X6CrNiNb18-10
- 309 / 309S AISI 309 · AISI 309S · SUS309S

#### Martensitic Stainless Steel

- AISI 410 SUS410 · EN 1.4006 · X12Cr13 · 12Cr13
- AISI 420 SUS420J1 · SUS420J2 · EN 1.4021 · EN 1.4028 · 20Cr13 · 30Cr13
- AISI 431 SUS431 · EN 1.4057 · X17CrNi16-2
- C1
- C3
- C4
- AISI 440A
- AISI 440B
- AISI 440C SUS440C · EN 1.4125

#### Ferritic Stainless Steel

- AISI 430 SUS430 · EN 1.4016 · X6Cr17 · 10Cr17
- F1
- AISI 434
- AISI 444

#### Precipitation-Hardening Stainless Steel

- 17-4 PH AISI 630 · UNS S17400 · SUS630 · EN 1.4542 · X5CrNiCuNb16-4
- 15-5 PH UNS S15500
- 17-7 PH UNS S17700

#### Duplex and Super Duplex Stainless Steel

- Duplex 2205 UNS S31803 · UNS S32205 · EN 1.4462
- Super Duplex 2507 UNS S32750 · EN 1.4410
- D2
- D4
- D6
- D8
- Lean Duplex 2101 UNS S32101
- Super Duplex S32760 UNS S32760 · EN 1.4501

### Carbon Steel

#### Low-Carbon Steel

- SAE 1006
- SAE 1008
- SAE 1010
- SAE 1018
- SAE 1020
- Q195
- Q235
- SAE 1012
- SAE 1015
- Q215
- ML08
- ML08Al
- ML10
- ML15
- ML20
- SWRCH6A
- SWRCH8A
- SWRCH10A
- SWRCH12A
- SWRCH15A
- SWRCH18A

#### Medium-Carbon Steel

- SAE 1035
- SAE 1045
- S45C
- C45
- SAE 1030
- SAE 1040
- SAE 1050
- 30
- 35
- 40
- 45
- 50
- S35C
- S40C
- S50C
- C35
- C40

#### High-Carbon Steel

- SAE 1060
- SAE 1070
- 65Mn
- SAE 1065
- SAE 1075
- SAE 1080
- SAE 1085
- SAE 1090
- SAE 1095
- 60
- 65
- 70
- 75
- 80
- 85

#### Cold-Heading Steel

- SWRCH22A
- 10B21
- SWRCH22K
- SWRCH25K
- SWRCH30K
- SWRCH35K
- SWRCH40K
- ML20Mn
- ML25
- ML30
- ML35
- ML40
- 15B25

### Alloy Steel

#### Chromium Steel

- 40Cr
- 45Cr
- AISI 5140
- SAE 5140
- AISI 5120
- SAE 5120
- SCr420
- SCr440

#### Chromium-Molybdenum Steel

- 35CrMo
- 42CrMo
- AISI 4140
- SCM435
- SCM440
- 42CrMo4
- 30CrMo
- AISI 4130
- SAE 4130
- SAE 4140
- AISI 4142
- AISI 4145
- SCM415
- SCM420
- SCM445
- EN 1.7220
- EN 1.7225
- 25CrMo4
- 34CrMo4

#### Nickel-Chromium-Molybdenum Steel

- AISI 4340
- SAE 4340
- 40CrNiMo
- SNCM439
- EN 1.6511
- 36CrNiMo4

#### Boron Alloy Steel

- 10B22
- 10B21
- 15B21
- 15B25
- 20MnTiB
- 20Mn2B
- 35VB
- 40MnB

### Bearing Steel

#### Bearing Steel

- GCr15
- AISI 52100 SAE 52100 · UNS G52986
- SUJ2
- 100Cr6 EN 1.3505
- GCr15SiMn

### Spring Steel

#### Carbon Spring Steel

- SAE 1065
- SAE 1070
- SAE 1075
- SAE 1080
- SAE 1095
- 65
- 70
- 75
- 80
- 65Mn

#### Silicon-Manganese Spring Steel

- 60Si2Mn
- 60Si2MnA
- SUP6
- SUP7

#### Chromium-Vanadium Spring Steel

- 50CrVA
- SAE 6150
- AISI 6150
- SUP10

#### Stainless Spring Steel

- AISI 301
- SUS301
- EN 1.4310
- AISI 302
- AISI 304
- AISI 316
- 17-7 PH

### Aluminum and Aluminum Alloys

#### Commercially Pure Aluminum

- 1050
- 1060
- 1070
- 1100

#### 2xxx Series Aluminum

- 2024
- 2011
- 2014
- 2017

#### 5xxx Series Aluminum

- 5052
- 5083
- 5754

#### 6xxx Series Aluminum

- 6061
- 6061-T6
- 6063
- 6082
- 6082-T6

#### 7xxx Series Aluminum

- 7075
- 7075-T6
- 7005
- 7050
- 7075-T73

### Brass

#### Free-Cutting Brass

- C36000
- H62
- HPb59-1
- C3601
- C3602
- C3604
- CuZn36Pb3
- CuZn39Pb3
- EN CW614N
- EN CW617N
- H65

#### Lead-Free Brass

- C69300
- C27450
- CW510L
- CW511L

#### Naval Brass

- C46400
- CuZn39Sn1

### Bronze

#### Silicon Bronze

- C65500
- C65100
- C65600

#### Phosphor Bronze

- C51000
- C52100
- CuSn6
- CuSn8

#### Aluminum Bronze

- C95400
- C95500
- C63000
- CuAl10Ni5Fe4

### Copper

#### Copper

- C11000
- T2
- C10100
- C10200
- C12200
- T1
- TU1
- TU2

### Titanium and Titanium Alloys

#### Commercially Pure Titanium

- Grade 2
- Grade 1
- Grade 3
- Grade 4
- TA1
- TA2
- TA3

#### Alpha-Beta Titanium Alloys

- Grade 5
- Ti-6Al-4V
- TC4
- UNS R56400

#### Low-Interstitial Grade

- Grade 23
- Ti-6Al-4V ELI
- UNS R56407

#### Other Titanium Fastener Alloys

- Ti-6Al-6V-2Sn
- Ti-6Al-2Sn-4Zr-2Mo
- Beta-C titanium
- Ti-10V-2Fe-3Al

### Nickel and Nickel Alloys

#### Commercially Pure Nickel

- Nickel 200
- UNS N02200
- Nickel 201
- UNS N02201

#### Inconel Alloys

- Inconel 625 UNS N06625
- Inconel 718 UNS N07718
- Inconel 600 UNS N06600
- Inconel 601 UNS N06601
- Inconel 686 UNS N06686
- Inconel X-750 UNS N07750

#### Monel Alloys

- Monel 400 UNS N04400
- Monel K-500 UNS N05500

#### Hastelloy Alloys

- Hastelloy C-276 UNS N10276
- Hastelloy C-22 UNS N06022
- Hastelloy B-2 UNS N10665
- Hastelloy B-3 UNS N10675
- Hastelloy X UNS N06002

#### Other Nickel Alloys

- Alloy 20 UNS N08020
- Alloy 625
- Alloy 718
- Alloy 825 UNS N08825
- Alloy 925 UNS N09925

### Iron-Nickel and High-Temperature Alloys

#### A286

- A-286
- UNS S66286
- EN 1.4980

#### Invar

- Invar 36
- Alloy 36
- UNS K93600
- FeNi36

#### Alloy 42

- Alloy 42
- UNS K94100
- FeNi42

### Tool Steel and Specialty Hardened Steel

#### Tool Steel and Specialty Hardened Steel

- AISI D2
- AISI H13
- SKD11
- Cr12MoV
- AISI O1
- AISI A2
- AISI S7
- SKD61
- 9CrSi

### Structural and Construction Steel

#### Structural and Construction Steel

- ASTM A36
- Q235B
- Q355B
- S355JR
- Q235C
- Q355C
- S235JR
- S275JR
- S355J2

## Applications & Industries for M2.5 Micro Small Countersunk Phillips Machine Screws

Micro Small Countersunk Phillips Machine Screws are bought for a small number of well-defined jobs. These are the ones we ship them for. Stocked from M1.4 to M2.6.

### Industries that specify Micro Small Countersunk Phillips Machine Screws

- **Microfabrication:** The head angle and diameter are checked against the prepared countersink.
- **Precision electronics:** Countersunk heads leave miniature covers flush where a projecting head would interfere.
- **Optical instruments:** Small flush screws hold frames and retainers in a narrow envelope.
- **Instrument repair:** Short lengths suit thin brackets and fine housings.
- **Energy & infrastructure:** Tower, pipework, switchgear and plant fixings specified for long service life and inspectable joints.
- **Maintenance & MRO:** Stocked replacements matched to an existing property class, thread and finish.

### Typical applications

- using the correct small cross driver
- seating a miniature screw flush in a countersunk hole
- matching the 90-degree seat to the parent part
- selecting a length that does not bottom in a blind tapped hole
- joints where the property class is stated on the drawing
- clamping two machined faces to a calculated preload

### Service conditions to specify against

- **Marine and coastal:** Available in A4 (316) stainless for chloride exposure — coastal structures, pool halls, water treatment and deck hardware, where A2 will eventually pit.
- **High load:** Supplied in ISO 898-1 property classes, so the joint can be designed to a stated proof load and tightened to a calculated torque rather than by feel.
- **Torque and preload:** The joint is designed around bolt tension, so lubrication, coating and the friction coefficient all change the torque figure — state them together.

### Where to use something else

- Do not force a countersunk head into a flat or undersized seat; the thin parent part can crack or dish.
- Do not use a machine thread into unthreaded sheet or timber; use a tapping screw, rivet nut or insert made for that parent material.

[Full application guide: where Micro Small Countersunk Phillips Machine Screws are used, how to specify them, and the cases they are wrong for](https://engineeringhardware.com/applications/micro-small-countersunk-phillips-machine-screws/)

Inside the plant

## Manufactured in our own plant

This part is cold-formed, threaded, heat-treated and finished in-house. The stages below are where its class and finish are actually decided.

1. ![Wire rod feeding into a cold heading machine](https://engineeringhardware.com/wp-content/uploads/2026/08/09-wire-rod-feed-cold-heading-machine.webp) 01 **Cold heading** Wire rod is drawn to size and cold-formed into blanks. Forming rather than cutting keeps the grain flow continuous around the head, which is where a bolt is most likely to fail. Head dimensions and under-head radius checked at set-up and per shift.
2. ![Thread rolling machine producing bolt threads](https://engineeringhardware.com/wp-content/uploads/2026/08/03-thread-rolling-machine-bolt-production.webp) 02 **Thread rolling** Threads are rolled between hardened dies rather than cut. Rolled threads are stronger in fatigue than cut threads and hold pitch and flank angle far more consistently across a batch. Go / no-go ring gauges to ISO 965 tolerance class 6g.
3. ![Baskets of bolts staged for heat treatment](https://engineeringhardware.com/wp-content/uploads/2026/08/05-heat-treatment-baskets-black-bolts.webp) 03 **Heat treatment** Quench-and-temper brings carbon and alloy steel to the property class ordered — 8.8, 10.9 or 12.9 — with the furnace charge tracked so a finished lot can be traced back to it. Core hardness and tensile tested per lot to ISO 898-1.
4. ![Zinc plated bolts in a treatment basket](https://engineeringhardware.com/wp-content/uploads/2026/08/23-zinc-plated-bolts-treatment-basket.webp) 04 **Surface treatment** Zinc, zinc-nickel, hot-dip galvanizing, black oxide, phosphate and Dacromet, selected against the service environment rather than against the price list. Coating thickness and neutral salt spray hours to ISO 9227.

## Frequently Asked Questions

### What's the typical proof load behavior of M2.5 class 8.8?

Micro-thread joints are sensitive to plastic deformation in the first turn under load — use a torque-limiting driver and check the bearing surface deformation on softer mating materials.

### Which Allen key fits M2.5 Micro Small Countersunk Phillips Machine Screws?

The hex-socket size for each row of Micro Small Countersunk Phillips Machine Screws is shown in the spec table — use the matching Allen / hex key. An ISO 2936 set covers every size on this page.

### How do I avoid stripping the socket on M2.5 Micro Small Countersunk Phillips Machine Screws?

Fully seat the key in the socket, choose ball-end keys only for low-torque finishing work, and prefer a T-handle key when feel matters. For production use a torque-controlled driver.

### What is the coarse-thread pitch of M2.5 for Micro Small Countersunk Phillips Machine Screws?

For M2.5 the standard coarse pitch is 0.45 mm — this is the value used for Micro Small Countersunk Phillips Machine Screws.

### How do I request a quotation?

Use the technical drawing on this page to pick the exact configuration, then submit it with the quote form. We respond within one business day.

## Related Pages

[View the full Micro Small Countersunk Phillips Machine Screws page](https://engineeringhardware.com/fastener/micro-small-countersunk-phillips-machine-screws/)

### More Micro Small Countersunk Phillips Machine Screws Guides