Odd bolt-tool-bit sizes.
Wheel nuts.
15mm Hex Smartcars (15mm impact socket ground down with tape wrapped round as not to mark alloy wheels)
22mm Hex Land Rover Discovery-Freelander, BMW X5
Cylinder head bolts.
Ribe M9 Fiat, VAG
Ribe M10 x 140mm VAG 1.8-2.0 V6
Ribe M12 x 120mm Fiat
Ribe M13 x 100mm Alfa, Fiat Lancia
Ribe M14 Fiat
Spline M9 Toyota
Spline M10 x 140mm Mercedes Sprinter
Spline M12 VAG, Ford, GM, Mercedes
Spline M14 VAG, Ford, Rover (plus Ford & VAG gearbox bellhousings)
E12 Female Torx BMW M42-50
Torx T50 Ford, Citreon
Torx T60 Ford 1.8Di
Torx T55 Renault
Torx T70 Ford
9mm Hex key VAG (allen key sawn & welded into a socket)
M12S Special 6 point Nissan
M8S Special 6 point Nissan head and balance shaft bolts
Toyota Idle pulley centre bolt
M10S Special 6 point
Nissan Renault Clutch
M6S Special 6 point
Nissan Balance shaft bolt
8TS Special female 3 point
Smartcar brake socket (plus some GM cars)
Five sided 14mm female socket
Brake socket
Five sided 10mm pentagon (assorted caliper bolts)
Citroen Peugeot Renault brake socket
Five sided 19mm pentogon
Nissan fuel pump
Five sided 12.5mm pentogon
Honda Civic lower control arms
20mm 10 point socket
New type Bosch freewheel alternators.
Torx T50 x long
Spline M10 x long
Modern clamp type diesel injectors.
11mm x 100mm Hex key (allen key sawn & welded into a socket)
Spline type sparkplug
Super long spline socket Citroen C5 fitted with Bosch 385R6 plugs (Laser tools cheapest option, part number: 3949)
Hub nuts.
30mm Six-sided deep socket VAG, Citroen, Fiat, Ford, Lada, Peugeot, Renault, Talbot, GM
30mm Shallow bi-hex VAG
32mm Six-sided deep socket Audi, Citroen, Fiat, Ford, Lancia, Peugeot, Renault, Talbot
33mm Six-sided deep socket VW late Golf front axles
35mm Six-sided deep socket Citroen BX, Rover, Peugeot J7-9
35mm Shallow bi-hex VAG T5
36mm Six-sided deep socket Alfa, Volvo, Citroen, Peugeot, Lancia, VAG (plus Saab ABS brakes & GM clutch bolts)
41mm Six-sided deep socket Alfa, Citroen, Peugeot, Fiat, Ford
45mm Six-sided BMW 5-series, LDV vans
46mm Six-sided BMW 3-series
50mm Bi-hex Transit 80-100-115-120 1988-on
52mm Six-sided Range Rover, Land Rover
56mm Deep bi-hex Transit 130-150-190 1993-on
65mm Bi-hex thin wall Transit 130-150-190 pre-1993
Spline M18 Tamperproof VW late Golf rear hubs
Headlight aligning adjusters.
Ribe M7 x 200mm Alfa, Fiat, Lancia
Early VAG clutch
9mm female spline
Oil filters.
38mm Six-sided GM Vectra 2.0D
27mm Six-sided-shallow Mercedes A-Class (cheap socket ground down to make a shallow one)
24mm Six-sided-shallow BMW V8 engines 2004> (cheap socket ground down to make a shallow one)
Drain plug keys.
Triangular bit Renault
10mm Female Sq BMW, Ford, Renault, Toyota (3/8" socket welded to a bar)
12mm Male Sq Alfa, Fiat, Lancia
10mm Male Sq Peugeot, Citroen , Renault, Volvo (3/8" short socket extension & filed down)
5mm Hex key Mercedes
Spline M16 Tamperproof VAG
VAG late doorhandles.
Spline M4
Fuel filter thru bolts.
13mm x 100mm Hex key Fiat, VAG (allen key sawn & welded into 1/2" six sided impact socket)
Gearbox sump covers.
Ribe M8 x long Alfa, Fiat, Lancia
Idle speed adjuster
Female E4 socket (tiny) Citroen Saxo (Draper sell 1/4" drive long one that fits down the hole)
Motorcycle wheel spindles. (hard black bolts with 19-22-24mm heads, welded into 1/2" sockets). Sealey sell a multipurpose tool for this purpose.
24mm Hex key Suzuki-Honda
22mm Hex key Kawasaki
19mm Hex key Yamaha
Motorcycle single sided swing arm rear spindle nuts
Ducati 999 - 998 - 996 - 916 - Monster - Multistrada - S2R - S4R Preferably six sided socket, but 12point will do the job. 46mm + 41mm needed.
Triumph preferably six sided socket 41mm
Mercedes Sensor Fixings
5 point Torx (male and female)
I truthfully never understand why manufacturers use odd size or style of bolts-fittings. The obvious answer is to try to prevent home mechanics enacting repairs, in truth it may be more to do with automated production tooling.
Spanner Jaw Sizes and corresponding Nut/Bolt Use |
Diff (mm) |
Jaw Size Millimetres |
Jaw Size Inches |
Spanner Metric |
Spanner AF |
Spanner British |
Common Nut/Bolt (*=non-preferred) |
2.97 | 0.117 | 10BA | ||||
0.23 | 3.20 | 0.126 | 3.2mm | M1.6 | ||
0.13 | 3.33 | 0.131 | 9BA | |||
0.53 | 3.86 | 0.152 | 8BA | |||
0.11 | 3.97 | 0.156 | 5/32 AF | No.0 UNC | ||
0.03 | 4.00 | 0.157 | 4mm | M2 | ||
0.37 | 4.37 | 0.172 | 7BA | |||
0.39 | 4.76 | 0.188 | 3/16 AF | No.2 UNC | ||
0.14 | 4.90 | 0.193 | 6BA | |||
0.10 | 5.00 | 0.197 | 5mm | M2.5 | ||
0.50 | 5.50 | 0.217 | 5.5mm | M3 | ||
0.06 | 5.56 | 0.219 | 7/32 AF | |||
0.03 | 5.59 | 0.220 | 5BA | |||
0.37 | 5.95 | 0.234 | 15/64 AF | |||
0.05 | 6.00 | 0.236 | 6mm | M3.5* | ||
0.30 | 6.30 | 0.248 | 4BA | |||
0.05 | 6.35 | 0.250 | 1/4 AF | No.4 UNC | ||
0.65 | 7.00 | 0.276 | 7mm | M4 | ||
0.14 | 7.14 | 0.281 | 9/32 AF | |||
0.02 | 7.16 | 0.282 | 3BA | |||
0.77 | 7.94 | 0.313 | 5/16 AF | No.6 UNC & No.10 UNC (bolt) |
||
0.06 | 8.00 | 0.315 | 8mm | M5 | ||
0.23 | 8.23 | 0.324 | 2BA | |||
0.36 |
8.59 |
0.338 |
1/8 W; 3/16 BSF | |||
0.15 |
8.73 | 0.344 | 11/32 AF | No.8 UNC |
||
0.27 | 9.00 | 0.354 | 9mm | |||
0.27 | 9.27 | 0.365 | 1BA | |||
0.25 | 9.53 | 0.375 | 3/8 AF | No.10 UNC (nut) |
||
0.48 | 10.00 | 0.394 | 10mm | M6 | ||
0.49 | 10.49 | 0.413 | 0BA | |||
0.51 | 11.00 | 0.433 | 11mm | M7* | ||
0.11 | 11.11 | 0.438 | 7/16 AF | 1/4 UNF | ||
0.19 | 11.30 | 0.445 | 3/16 W; 1/4 BSF | |||
0.70 | 12.00 | 0.472 | 12mm | |||
0.70 | 12.70 | 0.500 | 1/2 AF | 5/16 UNF | ||
0.30 | 13.00 | 0.512 | 13mm | M8 | ||
0.33 | 13.34 | 0.525 | 1/4 W; 5/16 BSF | |||
0.67 | 14.00 | 0.551 | 14mm | |||
0.29 | 14.29 | 0.563 | 9/16 AF | 3/8 UNF | ||
0.71 | 15.00 | 0.591 | 15mm | |||
0.24 | 15.24 | 0.600 | 5/16 W; 3/8 BSF | |||
0.64 | 15.88 | 0.625 | 5/8 AF | 7/16 UNF (bolt) |
||
0.13 | 16.00 | 0.630 | 16mm | |||
1.00 | 17.00 | 0.669 | 17mm | M10 | ||
0.46 | 17.46 | 0.688 | 11/16 AF | 7/16 UNF (nut) | ||
0.54 | 18.00 | 0.709 | 18mm | |||
0.03 | 18.03 | 0.710 | 3/8 W; 7/16 BSF | |||
0.97 | 19.00 | 0.748 | 19mm | M12 | ||
0.05 | 19.05 | 0.750 | 3/4 AF | 1/2 UNF | ||
0.95 | 20.00 | 0.787 | 20mm | |||
0.64 | 20.64 | 0.813 | 13/16 AF | 9/16 UNF (bolt) |
||
0.19 | 20.83 | 0.820 | 7/16 W; 1/2 BSF | |||
0.17 | 21.00 | 0.827 | 21mm | |||
1.00 | 22.00 | 0.866 | 22mm | M14* |
||
0.22 | 22.23 | 0.875 | 7/8 AF | 9/16 UNF (nut) | ||
0.78 | 23.00 | 0.906 | 23mm | |||
0.37 | 23.37 | 0.920 | 1/2 W; 9/16 BSF | |||
0.44 | 23.81 | 0.938 | 15/16 AF | 5/8 UNF | ||
0.19 | 24.00 | 0.945 | 24mm | M16 | ||
1.00 | 25.00 | 0.984 | 25mm | |||
0.40 | 25.40 | 1.000 | 1 AF | |||
0.25 | 25.65 | 1.010 | 9/16 W; 5/8 BSF | |||
0.35 | 26.00 | 1.024 | 26mm | |||
0.99 | 26.99 | 1.063 | 1-1/16 AF | |||
0.01 | 27.00 | 1.063 | 27mm | M18* | ||
0.94 | 27.94 | 1.100 | 5/8 W; 11/16 BSF | |||
0.06 | 28.00 | 1.102 | 28mm | |||
0.57 | 28.58 | 1.125 | 1-1/8 AF | 3/4 UNF | ||
1.43 | 30.00 | 1.181 | 30mm | M20 | ||
0.48 | 30.48 | 1.200 | 11/16 W; 3/4 BSF | |||
1.27 | 31.75 | 1.250 | 1-1/4 AF | |||
0.25 | 32.00 | 1.260 | 32mm | M22* | ||
1.02 | 33.02 | 1.300 | 3/4 W; 7/8 BSF | |||
0.32 | 33.34 | 1.313 | 1-5/16 AF | 7/8 UNF | ||
0.66 |
34.00 |
1.339 | 34mm |
|||
1.31 | 35.31 | 1.390 | 13/16 W? | |||
0.69 | 36.00 | 1.417 | 36mm | M24 | ||
0.51 | 36.51 | 1.438 | 1-7/16 AF | |||
1.08 | 37.59 | 1.480 | 7/8 W; 1 BSF | |||
0.41 | 38.00 | 1.496 | 38mm | |||
0.10 | 38.10 | 1.500 | 1-1/2 AF | 1 UNF | ||
2.03 |
40.13 | 1.580 | 15/16 W? | |||
0.87 | 41.00 | 1.614 | 41mm | M27* | ||
0.27 | 41.28 | 1.625 | 1-5/8 AF | |||
1.14 | 42.42 | 1.670 | 1 W; 1-1/8 BSF | |||
0.44 | 42.86 | 1.688 | 1-11/16 AF | 1-1/8 UNF | ||
3.14 | 46.00 | 1.811 | 46mm | M30 | ||
0.04 | 46.04 | 1.813 | 1-13/16 AF | |||
1.21 | 47.24 | 1.860 | 1-1/8 W; 1-1/4 BSF | |||
0.38 | 47.63 | 1.875 | 1-7/8 AF | 1-1/4 UNF | ||
2.38 | 50.00 | 1.969 | 50mm | M33* | ||
0.80 | 50.80 | 2.000 | 2 AF | |||
1.27 | 52.07 | 2.050 | 1-1/4 W; 1-3/8 BSF | |||
0.32 | 52.39 | 2.063 | 2-1/16 AF | 1-3/8 UNF | ||
2.61 | 55.00 | 2.165 | 55mm | M36 | ||
0.56 | 55.56 | 2.188 | 2-3/16 AF | |||
0.83 |
56.39 |
2.220 |
1-3/8 W; 1-1/2 BSF |
|||
0.76 |
57.15 | 2.250 | 2-1/4 AF | 1-1/2 UNF | ||
2.85 |
60.00 | 2.362 | 60mm | M39* |
Page updated 28-05-18