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

M4 Hollow Wall Anchors (Molly Bolts) Dimensions

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

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 sizeDrill hole diameter (mm)Wall thickness range (mm)Anchor length (mm)Flange diameter (mm)SettingMaterialScrew retained
M483~133211.0Screw-set / setting toolZinc plated steelYes 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 manufacturingSend a drawing

Technical Drawing

Customize the parameters below — every spec field is editable, and the drawing redraws to match the values you choose. Changing the size will snap the other fields to that size's standard values; you can then override any individual value.

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
Sends the selected values to the quote form below.

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The form below follows the current technical drawing configuration. Change the drawing values above and the request details update automatically.

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Specification
Business Information

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

Screw sizeDrill hole diameter (mm)Wall thickness range (mm)Anchor length (mm)Flange diameter (mm)SettingMaterialScrew retained
M483~133211.0Screw-set / setting toolZinc plated steelYes u2014 removable
M5105~203813.0Screw-set / setting toolZinc plated steelYes u2014 removable
M51013~305213.0Screw-set / setting toolZinc plated steelYes u2014 removable
M6125~254516.0Screw-set / setting toolZinc plated steelYes u2014 removable

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

Video: M4 Hollow Wall Anchors (Molly Bolts) Dimensions

Third-party video, selected automatically for this topic. It is not produced by Engineering Hardware and is not a specification source — use the tables on this page for dimensional data.

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
    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
    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
    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
    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.