Spanner Screwdriver Size Chart

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Spanner jaws to the exact rated size, using a high-tech grinding machine. Perfect fit is the most important requirement for non-damaging and safe work. Protects bolt heads. The Tamperproof spanner screwdriver is a complete security screwdriver set in one driver. Spanner: 6, 8, 10, 12. Security SAE Hex: 1/8, 9/64, 5/32, 3/16in.

Kevin C Bacon.(Baconsdozen Imperial tools).
Commonly used Whitworth or B.S.F to SAE / A.F (inches across flats) sizes and conversions to metric and decimal inch dimensions.
I've prepared these charts from my own experience and research.They are all my own,original work,not plagarised from other web sites or the 'experts' on ebay.If they appear anywhere else,they have been copied from here.
The imperial (BSW,BA and AF) tools I have for sale along with extra clearance items are on this single page.
Commonly used Whitworth/BSF thread dia and the mm or imperial (inch) size of the wrench opening to fit nut or head.
Whitworth (inch).
BSF.(inch).
Actual Metric.(mm)
Actual Inches (decimal)
1/8
3/16
8.64
.340
3/16
1/4
11.3
.445
1/4
5/16
13.34
.525
5/16
3/8
15.24
.6
3/8
7/16
18.03
.710
7/16
1/2
20.83
.82
1/2
9/16
23.37
.92
9/16
5/8
25.65
1.010
5/8*
11/16*
27.94*
1.100
11/16**
3/4
30.48
1.200
3/4*
7/8*
33.02*
1.300
7/8
1
37.59
1.480
1
1 .1/8
42.42
1.670

1 .1/8

1 .1/4

47.24

1.860
  1. Steering Rack - 4 screws - 9. Left/Right Wishbone - 2 screws - 10. Left/Right Steering Rod - 1 screw - 12. Screw in after Strut is placed. Adjustment nut - size 14. Spindle - 1 screw - 12. Disk Brake - 1 screw - 14. Don't tighten until Half Shaft is in. Left/Right Strut - 4 screws bottom, 3 nuts top - 9 bottom, 10 top.
  2. Drilled Spanner: No. 10 (1' O'all Lg.) Tri-Wing®: No. 5 (1' O'all Lg.) 1/8'.
  3. Magneto Spanner. It is a bunch of small sized single-end spanner. Spanners of different sizes are tied together for tightening or opening small nut bolts. These are thin steel rods with six faces that are bent at 90° angles from one end. These are used to open such bolts whose heads are made round.
  4. 11320 FM 529 RD BLDG F HOUSTON, TEXAS 77041 TEL (713) 896- 1166 FAX (713) 896-7879 Tool Size Chart Inch Fasteners Metric Fasteners Wrench Sizes (in.) Hex Key Sizes (in.) Wrench & Hex Key Sizes (mm) Diameter Hex Heavy Hex Diameter Socket Diameter Hex Socket 1/4 7/16 #1 1/16 M3 5.50 2.50.

Notes.
*You can use the above chart (and the AF/metric chart below) to find equivalents for some missing tools.For example 5/8 inch whit and 28mm,3/4 inch whit and 33mm etc. Some sockets especially six sided impact might be marked in these examples with both sizes.The longer list at the bottom of the page lists all common sizes in numerical order.

** 11/16 inch is not a commonly encountered Whitworth size,13/16 inch and 15/16 inch are even less so and were very seldom specified on engineering drawings etc.

A few explanations.....
British Standard Whitworth (B.S.W) takes its name from the British engineer who invented it as a way of standardising bolt and nut sizes.Whitworth threads are based on an angle of 55 degrees.Commonly found on older (pre 60's) vintage,veteran and classic cars,bikes or early machinery,there are two 'standards' of Whitworth, as during 1924 the sizes of nuts and bolt heads were reduced to save iron and steel.They were all reduced by one size,so that the same spanners and sockets can still be used. The war also demonstrated the need for a standard for nuts.bolts and the tools to work on them as British (mainly BSW and BSF) and US (UNF and UNC) machinery used completely different systems.
British Standard fine is in effect the fine version of whitworth with the same thread form but with a greater number of threads per inch.The size marked on a Whitworth or B.S.F (British Standard Fine) spanner refers to the size in inches of the threaded portion on the bolt it fits. Both Whitworth and British Standard Fine were phased out by the 1960s,but some manufacturers carried on using both on applications much later than this. Whitworth thread is coarser than a BSF of the same diameter,but the same spanners are used on both ranges,and are often marked with both Whitworth and BSF sizes .A whitworth spanner or socket is larger than one marked with the same size in BSF for example a 1/4 inch whit is the same physical size as a 5/16inch BSF.(approx 13.34mm),this occurs throught the sizes so a set of whitworth sockets or spanners will fit an equal number of BSF nuts and bolts.The easiest way to identify a whitworth or BSF threaded bolt is to measure its diameter and check the thread rate (TPI or threads per inch) with a thread gauge and compare it to the charts below.BSW and BSF socket head screws use AF hex keys not metric.

B.A (British Association) are smaller sized fastenings found on older vehicles electrical fittings,magnetos,dynamos,motors,pumps and instruments etc. B.A thread has an angle of 47 degrees-30 minutes.This was another standard introdued to try and rationalise the sizes of smaller fixings.

A.F means Across Flats and indicates the distance apart the jaws are on an open end wrench (or the parallel sides on a nut or bolt. Usually applied to spanners in imerial (inch based) sizes the smallest increments are normally 1/16 inch (for example 7/16,1/2,9/16 etc) but some smaller spanners are marked in 1/32 inch increments.Very rarely af spanners are marked in decimal instead of fractional sizes for example .50 instead of 1/2 or .75 instead of 3/4 inch etc.Imperial AF spanners are normally used on nuts and bolts threaded UNC or UNF (Unified Coarse or Unified Fine) and use a thread angle of 60 degrees.This standard was introduced as the 'new' standard around the 1940s to replace BSW and BSF etc and was supposedly phased out by the 1970's in favour of metric threads and sizes. However like whitworth and BSF,AF it is still encountered in specialised applications and many car and motorbike makers carried on using imperial fittings etc for a long time after they became supposedly obsolete. It is very common to find an older car or bike that left its maker with a mixture of imperial and metric nuts and bolts holding it together. Land Rover and other smaller,specialised car makers used a mixture of imperial fittings into the 1990's.Note also that AF allen or hex keys fit BSW or BSF hex headed socket screws.
Modern metric spanners are marked or sized in the same way as AF but in millimetres,the distance again between parallel faces of an open ended spanner or wrench.They are used on metric threaded fastenings,these have a thread angle of 60 degrees.Metric bolts often have two numbers on the heads,this is a strength rating.
Coarse threads (whitworth,unc etc) are more likely to be used on the thread in a casting to give greater strength,most nut and bolt assemblies will use a fine thread,so studs in castings often have a coarse thread end to go in the casting and a fine end to take a nut.Finer threads (BSF,unf etc) have a greater resistance to being shaken loose by vibration.Bolts and nuts in brass or similar soft metal are normally coarse threaded for greater holding power..

AF spanners and sockets (across flats in inches) to Metric (mm).

Bolt dia.

AF spanner size inches

Spanner size MM

1/4 inch

6.35 mm

5.16 inch

7.94 mm

3/8 inch

9.52 mm

1/4 inch

7/16 inch

11.11 mm

5/16 inch

1/2 inch

12.7 mm

3/8 inch

9/16 inch

14.29 mm

7/16 inch

5/8 inch

15.88 mm

11/16 inch

17.46 mm

1/2 inch

3/4 inch

19.05* mm

9/16 inch

7/8 inch

22.22 mm

5/8 inch

15/16 inch

23.81 mm

1.00 inch

25.40 mm

1.1/16 inches

26.93 mm

3/4 inch

1.1/8 inches

28.57 mm

Diameter and thread pitches in inches (tpi) for BSW, BSF, UNC and UNF bolt threads
This chart can be used to help identify the thread on a bolt etc. Measure the outside diameter and then count the number of threads per inch. UNC and Whitworth have the same thread rates but the thread form is different,a thread gauge would help to make accurate comparisons.Take into account also the age of the vehicle or machine the fitting is from. Pre 60s Whitworth is more likely,unified threads started replacing BSW and BSF from the early 1950s but the change was spread over many years in some cases.


BA spanner and socket sizes in inches with metric (mm) equivalents
BA (British Associated) is an early British standard often found on dynamos,magnetos,distributors,starters and electrical fittings and connections on older British cars and motorcycles.
The smaller the number the larger the BA nut and bolt. BA sizes right down to 24BA are in fact used.although 10BA is the smallest normally encountered.The thread per inch rate is always a fraction (ie) never a whole number varying from 25.4 (0BA) to 72.6 (10BA) for example.

Number BA

BA spanner size across flats in decimal inches.

Metric equivalent

10BA

.117 inches.

2.97mm

9BA

.131 inches

3.33 mm

8BA

.152 inches

3.86mm

7BA

.172 inches

4.37mm

6BA

.193 inches

4.90mm

5BA

.220 inches

5.59mm

4BA

.248 inches

6.30mm

3BA

.282 inches

7.16mm

2BA

.324 inches (Probably the most commonly used BA size)

8.23mm

1BA

.365 inches

9.27mm

0BA

.413 inches

10.49mm.


Application chart for some hub nut,ball joint sockets and box spanners etc (mainly older vehicles).
Our hub nut and ball joint sockets and spanners are listed on the relevant pages (ie)AF or SAEand BSW (Whitworth)
Size
Applications
Vehicles
Notes
3/4 inch af
Common wheel nut size.
Very common.11/16 AF commonly used on smaller.
(19mm equivalent )
15/16 inch af
Wheel nuts
Pre 1972 Land Rovers
(24mm)
1 + 1/16 af
Wheel nuts
After 1972 Land Rovers.
(27mm)
1 +1/4 inch af
Rear hub nut
Jowett Javelin
Virtually every nut and bolt on these vehicles is whitworth or BSF.
1 + 5/16 inch af 6 point deep socket
Front hub nuts.
 Mini,Austin Allegro,Austin/Morris 1100 and 1300 Austin Maxi.

Front wheel drive hub nuts.Also cranshaft pulley and rear hub on MGB.

1 + 1/2 inch af.6 point deep socketFront suspension ball joints Mini,Allegro.Austin/Morris 1100 or 1300,Maxi. Also fits Mini flywheel nuts.
1 + 5/8 inch af
Rear Hub nut.
BMC Midget,Austin Healey Sprite etc.

Probably other early BMC rear wheel drive A40 etc.

1 + 3/4 inch (socket or box)

Ball joints.

Some early Leyland vehicles

Socket must be deep type for ball joint application.

1 + 13/16 inch af 6 point deep socket

Front suspension ball Joints

Rover group Metro vehicles
Also ...Modern Triumph motorbikes?.

Normally impact type.1/2 inch square drive.
1 + 7/8 inch af
Hub nuts
 Older BMC (Wolseley 1500 etc). Available as H/D box or socket.
2 inch AF.

Hub nuts

Land Rover etc (used as substitute for 52mm)

See list at foot of page.**

2 +13/16 inch af
Rear hub nuts
Commer TS3
Rear hub nuts.Front uses 42mm
2 +3/4 inch af
Hub nuts
Bedford 2 Ton
70mm.
3 inch af
Hub nuts
Bedford 3 Ton
3 + 1/8 inch af
Hub nuts
Leyland Roadrunner
 Also some IVECO trucks
7/16 inch whitworth

Scaffold Spanner

  • Scaffold clamps.(with a pointed end the spanner is often called a 'podger spanner').
Still often used but being replaced by metric.
1 +1/8 inch whitworth
Hub Nuts

Morris Minor and other BMC vehicles

 Available as deep socket or box.
1 +1/4 inch whitworth.
Burman gearbox

(Panther,Vincent motorcyles and many others)

  • Nearest equivalent 52mm as below.**
22 mm deep
  • Oxygen Sensor

Modern vehicles

 Long socket often has 'window' in side.
27 mm deep

M24 threaded injector sockets.

Most diesel injector sockets cars and light commercials..

Will also fit some sensors.

28mm deep

HGV diesel injector sockets

Scania,Volvo
 Larger diesel injector sockets on many HVG engines.
52mm six sided socket
Hub nut **
 Some models Land Rover and Range Rover
close equivalent is 2 + 1/16 inch af.
56mm (usually 12 sided)
Hub nut

Ford Transit 1993 onwards.

Usually 3/4 drive.

65 mm (usually 12 sided)
Hub nut

Ford Transit (before 1993)

Ford Transit models 130,150 and 190 plus some IVECO.
50mm Eight sided
Hub nut

Austin A55,MGA.MGB*

Note these are octagonal (eight sided).*
56mm Eight sided
Hub nut

J2 Van and some early taxi cabs*

 As above (eight sided).*
All the commonly used spanner and socket sizes,from 10BA up to 60mm with their decimal inch equivalents.
This chart shows comparative sizes in increasing B.A, A.F, B.S.W, B.S.F and MM bolt or nuts and can be used for example to find the next size up or down where a spanner (wrench in USA) or socket is too tight or loose on a fixing. It also shows when some spanners and sockets are almost the same physical size although displaying different markings for example 11/32 inch AF and 1/8 inch whitworth are identical. Note that a set of spanners marked in whitworth (often abbreviated just to 'W') or sockets will cover both the whitworth standards (pre and post war) and the BSF ranges, you do not (as some naughty or just ill informed web sites suggest) need to buy two sets!.
0.131 inches = 9 BA
0.172 inches = 7 BA
0.220 inches = 5 BA
0.250 inches = 1/4 inch AF

How To Identify Spanner Size

0.282 inches = 3 BA
0.315 inches = 8mm
0.344 inches = 11/32 AF and 1/8 Whitworth
0.365 inches = 1 BA
0.394 inches = 10mm

Spanner Screwdriver Size Chart Actual

0.413 inches = 0 BA (Largest BA size)
0.438 inches = 7/16 inch AF
0.472 inches = 12mm
0.512 inches = 13mm
0.531 inches = 17/32 inch AF (13.49 mm)
0.563 inches = 9/16 inch AF
0.594 inches =19/32 inch AF (15.1 mm)
0.625 inches = 5/8 inch AF
0.669 inches = 17mm
0.709 inches = 18mm (uncommonly used metric spanner size) but often used as a substitute for 3/8 inch whit..
Spanner Screwdriver Size Chart
0.748 inches = 19mm
0.781 inches =25/32 inch AF (19.8mm)
0.813 inches = 13/16 AF inch (Common spark plug size).
0.866 inches = 22mm
0.920 inches = 1/2 Whitworth or 9/16 BSF
0.945 inches = 24mm
1.010 inches = 9/16 Whitworth or 5/8 BSF
1.063 inches = 1 + 1/16 AF inch or 27mm
1.105 inches = 28mm often used as a substitute for 5/8 inch whit (actually .005inch larger).
1.181 inches = 30mm
1.250 inches = 1 + 1/4 inch AF
1.300 inches = 3/4 Whitworth or 7/8 BSF
1.313 inches = 1 + 5/16 inch AF (some ball joints).
1.390 inches = 13/16 Whitworth or 15/16 BSF (not very commonly used).
1.438 inches = 1 + 7/16 inch AF
1.495 inches = 38mm.
1.575 inches = 40mm or 15/16 inch Whitworth
1.625 inches = 1 + 5/8 inch AF
1.688 inches = 1 + 11/16 inch AF
1.813 inches = 1 + 13/16 inch AF
1.875 inches = 1 + 7/8 inch AF
2.000 inches = 2 inch AF,(A fairly common hub nut size).** see notes in above table.
2.047 inches = 52mm (Some land rover hub nuts) used as substitute for 1 + 1/4 inch whitworth (actually .003 smaller).
2.050 inches = 1 + 1/4 Whitworth or 1 + 3/8 BSF,(another common hub nut size).
2.165 inches = 55mm
A tubular box spanner or six sided socket the next size up might be a solution when the correct size is not available (ie) a 19mm spanner will probably undo a 3/4 inch af nut.These may have greater tolerance than 12 sided sockets but there is always a risk of damage to socket and or the fastening. Most impact sockets are six sided. Six sided (sometimes called six point) sockets or ring spanners are also less likely to damage brass or chrome plated fittings.
Whitworth,BSF,metric and imperial spanners are based on different standards and hence sizes,with few exceptions they are not interchangeable..As well as classic motorcycles from AJS to Vincents,a lot of older cars used whitworth and BSF fastenings .Marine engines like Lister and Gardner use them as well, and were designed to last, so imperial tools might be regarded as obsolete by some but are still essential on such units..
Damaged bolt heads spoil the restoration or repair of many a rebuilt classic car or motorcycle,theres no need when the correct spanners are still available .Ring spanners are called box spanners in the US,block spanner is another term for an obstruction spanner and some people refer to C obstruction spanners as crescent wrenches,others use the same term for an adjustable spanner.
If you are still unsure as to what spanner or socket you require to order,measure the nut or bolt with a caliper or accurate ruler across the flats in mm.If you know if the thread is fine or coarse and when the item was made it will help work out what size the original fitting is. Some axle shaft nuts are eight sided,normal bi hex sockets will not fit these

Spanner Screwdriver Size Chart

My Home page is here.

Some web sites state that Whitworth and UNC fixings are interchangeable.This is not strictly correct,although some will loosely 'fit' the thread angle on Unified threads is 60 degrees against the 55 of Whitworth.The thread rates are also different (ie) 1/2 inch whit is 12 tpi and for 1/2 inch UNC is 13.tpi. Other thread forms that may be encountered on older machinery include BSP (British Standard Pipe) on fuel,air or oil lines etc and very rarely and on much older machinery BCS (British Standard Cycle).

How To Check Spanner Size

Kevin C Bacon

Baconsdozen Imperial tools

Spanner Screwdriver Size Chart Inches

Tel (44) 01472353993 Mobile 07974435627..