---
title: "M4 Hollow Wall Anchors (Molly Bolts) Dimensions"
description: "M4 Hollow Wall Anchors (Molly Bolts): coarse thread pitch 0.7 mm. Full size chart to Trade series (metal cavity anchor) with tolerances."
url: https://engineeringhardware.com/guide/size/m4-hollow-wall-anchors/
source: Engineering Hardware & Fasteners
---

# M4 Hollow Wall Anchors (Molly Bolts) Dimensions

Anchors & Concrete Fixings · Trade series (metal cavity anchor)

Controlling dimensions to Trade series (metal cavity anchor), with tolerances and fit.

M4 Hollow Wall Anchors (Molly Bolts) dimensions to Trade series (metal cavity anchor): coarse thread pitch 0.7 mm.

- **Coarse thread pitch:** 0.7 mm

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

![M4 Hollow Wall Anchors (Molly Bolts) Dimensions reference image](https://engineeringhardware.com/wp-content/uploads/2026/08/Hollow-Wall-Anchors.webp)

The M4 size of Hollow Wall Anchors (Molly Bolts) is dimensioned by Trade series (metal cavity anchor). The table below gives the dimensional row from the standard, followed by the installation notes for this type.

Values are taken from the governing standard rather than from a general machine-thread table, because this type is not selected on one.

## M4 Dimensional Row (Trade series (metal cavity anchor))

| Screw size | Drill hole diameter (mm) | Wall thickness range (mm) | Anchor length (mm) | Flange diameter (mm) | Setting | Material | Screw retained |
| --- | --- | --- | --- | --- | --- | --- | --- |
| M4 | 8 | 3~13 | 32 | 11.0 | Screw-set / setting tool | Zinc plated steel | Yes u2014 removable |

Custom manufacturing · Made to drawing

## Need hollow wall anchors (molly bolts) in a size this table does not list?

This page covers M4 hollow wall anchors (molly bolts). Length and corrosion protection are the usual specials. The load a fixing will take is decided by the concrete and the edge distance, not by ordering a longer anchor. Made by hot forging or thread rolling.

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

[Custom anchor & concrete fixing manufacturing](https://engineeringhardware.com/custom/anchors/)[Send a drawing](https://engineeringhardware.com/custom/anchors/#rfq)

## Technical Drawing

Dimensioned line drawing of M4 Hollow Wall Anchors (Molly Bolts) to Trade series (metal cavity anchor). Side view and top view, drawn to the dimensions in the table below and redrawn for any size selected.

- **Drill hole diameter (mm):** 8
- **Wall thickness range (mm):** 3~13
- **Anchor length (mm):** 32
- **Flange diameter (mm):** 11.0
- **Setting:** Screw-set / setting tool
- **Material:** Zinc plated steel
- **Screw retained:** Yes u2014 removable

## Dimensions & Specifications (Trade series (metal cavity anchor))

| Screw size | Drill hole diameter (mm) | Wall thickness range (mm) | Anchor length (mm) | Flange diameter (mm) | Setting | Material | Screw retained |
| --- | --- | --- | --- | --- | --- | --- | --- |
| M4 | 8 | 3~13 | 32 | 11.0 | Screw-set / setting tool | Zinc plated steel | Yes u2014 removable |
| M5 | 10 | 5~20 | 38 | 13.0 | Screw-set / setting tool | Zinc plated steel | Yes u2014 removable |
| M5 | 10 | 13~30 | 52 | 13.0 | Screw-set / setting tool | Zinc plated steel | Yes u2014 removable |
| M6 | 12 | 5~25 | 45 | 16.0 | Screw-set / setting tool | Zinc plated steel | Yes u2014 removable |

Product catalog

## Related Hollow Wall & Toggle Anchors products

[![The Factory Custom OEM Precision Automatic Lathing Lock Spring Toggle Bolts](https://img.engineeringhardware.com/The-Factory-Custom-OEM-Precision-Automatic-Lathing-Lock-Spring-Toggle-Bolts.webp)](https://engineeringhardware.com/product/the-factory-custom-oem-precision-automatic-lathing-lock-spring-toggle-bolts/)

Hollow-Wall & Toggle Anchors

### [The Factory Custom OEM Precision Automatic Lathing Lock Spring Toggle Bolts](https://engineeringhardware.com/product/the-factory-custom-oem-precision-automatic-lathing-lock-spring-toggle-bolts/)

Round Head · DIN, ANSI, GB, JIS

**US$6.00 – 24.00**MOQ 1,000 pieces

[![High Quality Carbon Steel Bolt Anchor Heavy Duty Hollow Wall Anchors](https://img.engineeringhardware.com/High-Quality-Carbon-Steel-Bolt-Anchor-Heavy-Duty-Hollow-Wall-Anchors.webp)](https://engineeringhardware.com/product/high-quality-carbon-steel-bolt-anchor-heavy-duty-hollow-wall-anchors/)

Hollow-Wall & Toggle Anchors

### [High Quality Carbon Steel Bolt Anchor Heavy Duty Hollow Wall Anchors](https://engineeringhardware.com/product/high-quality-carbon-steel-bolt-anchor-heavy-duty-hollow-wall-anchors/)

ANSI, BSW, DIN, GB, JIS, ISO · Low Carbon Steel

**US$0.17 – 0.18**MOQ 8,000 pieces

[![Heavy Duty Toggle Bolt Spring Butterfly Anchor in Stock](https://img.engineeringhardware.com/Heavy-Duty-Toggle-Bolt-Spring-Butterfly-Anchor-in-Stock.webp)](https://engineeringhardware.com/product/heavy-duty-toggle-bolt-spring-butterfly-anchor-in-stock/)

Hollow-Wall & Toggle Anchors

### [Heavy Duty Toggle Bolt Spring Butterfly Anchor in Stock](https://engineeringhardware.com/product/heavy-duty-toggle-bolt-spring-butterfly-anchor-in-stock/)

GB, DIN, ISO, ANSI/ASTM, BS, BSW, etc · Stainless Steel & Carbon Steel

**US$0.001 – 0.0034**MOQ 100 pieces

[![Petal Rivet Nuts Expansion Nut Fixings Steel Black Molly Jack Nut](https://img.engineeringhardware.com/Petal-Rivet-Nuts-Expansion-Nut-Fixings-Steel-Black-Molly-Jack-Nut.webp)](https://engineeringhardware.com/product/petal-rivet-nuts-expansion-nut-fixings-steel-black-molly-jack-nut/)

Hollow-Wall & Toggle Anchors

### [Petal Rivet Nuts Expansion Nut Fixings Steel Black Molly Jack Nut](https://engineeringhardware.com/product/petal-rivet-nuts-expansion-nut-fixings-steel-black-molly-jack-nut/)

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

**US$0.012 – 24.00**MOQ 500 pieces

[![Fastener Supplier Zinc Plated Steel Spring Toggle Wing Anchor for Hollow Wall / Drywall / Plasterboard](https://img.engineeringhardware.com/Fastener-Supplier-Zinc-Plated-Steel-Spring-Toggle-Wing-Anchor-for-Hollow-Wall-Drywall-Plasterboard.webp)](https://engineeringhardware.com/product/fastener-supplier-zinc-plated-steel-spring-toggle-wing-anchor-for-hollow-wall/)

Hollow-Wall & Toggle Anchors

### [Fastener Supplier Zinc Plated Steel Spring Toggle Wing Anchor for Hollow Wall / Drywall / Plasterboard](https://engineeringhardware.com/product/fastener-supplier-zinc-plated-steel-spring-toggle-wing-anchor-for-hollow-wall/)

GB, DIN, ISO, ANSI/ASTM, BS, BSW, etc · Stainless Steel & Carbon Steel

**US$0.0024 – 0.0048**MOQ 3,000 pieces

[![Wholesale Plastic Expansion Drywall Anchor Manufacturer and Supplier Hollow Wall Anchor](https://img.engineeringhardware.com/Wholesale-Plastic-Expansion-Drywall-Anchor-Manufacturer-and-Supplier-Hollow-Wall-Anchor.webp)](https://engineeringhardware.com/product/wholesale-plastic-expansion-drywall-anchor-manufacturer-and-supplier-hollow-wall/)

Hollow-Wall & Toggle Anchors

### [Wholesale Plastic Expansion Drywall Anchor Manufacturer and Supplier Hollow Wall Anchor](https://engineeringhardware.com/product/wholesale-plastic-expansion-drywall-anchor-manufacturer-and-supplier-hollow-wall/)

DIN, GB · PA

**US$0.0156 – 0.0252**MOQ 1,000 pieces

[View all Hollow-Wall & Toggle Anchors →](https://engineeringhardware.com/fastener-products/anchors-construction-fixings/hollow-wall-toggle-anchors/) [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 M4 Hollow Wall Anchors

The sectors that buy Hollow Wall Anchors, and the duty each one buys them for. Stocked from M4 to M6.

### Industries that specify Hollow Wall Anchors

- **Domestic & light commercial:** TV brackets, cabinets and grab rails.
- **Drylining & partitions:** Rails, brackets and fittings fixed to plasterboard.
- **Fit-out & shopfitting:** Loads spread behind a board where there is no stud.
- **Building services:** Suspending tray, duct, pipe and sprinkler runs from a soffit.
- **Plant installation:** Machines and equipment held down to a concrete floor.
- **Fit-out & drylining:** Fixings into board, block and hollow wall.

### Typical applications

- toggles for the highest load, sleeve anchors where the fixture is removed
- spreading the load behind a hollow board
- suspended services on threaded rod
- making a load-bearing threaded fixing in concrete or masonry
- fixing a steel fixture through to a solid substrate

### 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.
- **Hole preparation:** Drilled diameter, depth and cleanliness are part of the specification; an uncleaned hole is the single most common cause of a failed anchor.
- **The concrete governs:** Capacity is a property of the base material and the geometry — grade, edge distance, spacing and cracked or uncracked — not of the anchor alone. Work to the anchor manufacturer's ETA or ICC-ES report.

### Where to use something else

- Not for a substrate the type is not qualified in — an expansion anchor near an edge or in hollow block will split it.

[Full application guide: where Hollow Wall Anchors are used, how to specify them, and the cases they are wrong for](https://engineeringhardware.com/applications/hollow-wall-anchors/)

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 clearance and tapping drill suit M4?

Use a 4.5 mm clearance hole (ISO 273 medium) for through-fixing, or a 3.3 mm tapping drill for a coarse M4 thread.

### Is M4 Hollow Wall Anchors (Molly Bolts) suitable for electronics and small mechanisms?

M4 Hollow Wall Anchors (Molly Bolts) is in the micro range and is widely used in electronics, instrument enclosures and small precision mechanisms. Watch the over-torque margin — micro joints strip easily.

### What's the typical proof load behavior of M4 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.

### What is the coarse-thread pitch of M4 for Hollow Wall Anchors (Molly Bolts)?

For M4 the standard coarse pitch is 0.7 mm — this is the value used for Hollow Wall Anchors (Molly Bolts).

### 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 Hollow Wall Anchors (Molly Bolts) page](https://engineeringhardware.com/fastener/hollow-wall-anchors/)

### More Hollow Wall Anchors (Molly Bolts) Guides