Metric Bolt Sizes

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What is Metric Bolt Sizes?

Metric bolts sizes are referenced using “M” sizes, such as the M6 bolt size. The size of a metric bolt is specified using pitch, diameter, and length in millimeters. For example, in M6-1.0*20, the “M” means the Metric thread designation, the digit 8 refers to the Nominal diameter (in millimeters), 1.0 refers to the pitch, and 20 refers to the length. Sometimes, the pitch is omitted in the abbreviated format, such as M6-20, this means the bolt has a coarse thread. The bolt dimension can also be expressed in imperial units. 

1. Diameter: the width of the bolt shank, the bolt head is not included. The defined diameter of metric bolts is actually slightly larger than the actual diameter. So an M6 bolt would have a diameter that’s slightly under 6mm.

2. Pitch: the measurement between the apex of adjacent threads on the bolt’s shank, equal to the ratio of threads to unit length. Metric bolts are available with either coarse or fine thread pitches. Metric bolts with a coarse thread pitch have more threads per inch than comparable imperial bolts.

3. Length: for socket head, pan head, button head, and hex head bolts, the length measurement from the chamfered edge to the undercut of the head, and the bolt head is not included. But for flat head bolts, the length includes the height of the bolt head and for dome head bolts the length is measured from the highest point on the curved head. The length of a metric bolt is measured and defined in exactly the same way as imperial bolts,screws(fasteners)

Metric Bolt Sizes

Metric Hex Bolt Sizes

Hex bolts have hexagonal heads and machine threads for use with a nut or in a tapped hole. Also known as hex cap screws or machine bolts.Hex bolts are designed with a hexagonal head that to be driven by a wrench and external machine threads, maybe partially threaded or fully threaded.below is Metric Hex Bolt Sizes

Metric Bolt Sizes
Screw Thread(d)M3M4M5M6M7M8M9M10M12M14M16M20
PPitch0.50.70.8111.251.51.51.51.51.51.5
dsmax345678101214161820
dsmin2.93.884.885.886.857.859.8511.8213.8215.8217.8219.79
smax5.578101113171922242730
smin5.386.857.859.7810.7312.7316.7318.6721.6723.6726.6729.67
kk2.52.533.544.5566.57.589
Metric Bolt Sizes

Metric Square Head Bolt Sizes

Square head bolt design enables an easier wrench grip for nut tightening. They are usually used in new construction along with square plate washer and taper washers. There is also a requirement to mimic an older fastener aesthetic in both new and old buildings.below is square head bolt sizes

Metric Bolt Sizes
Screw Thread(d)M6M8M10M12M14M16M18M20M22M24
PPitch11.251.51.75222.52.52.53
dsmax+nominal size681012141618202224
dsmin5.87.89.811.7513.7515.7517.7519.6521.6523.65
kNominal Size45.57891012131415
kmax4.255.757.38.39.310.3512.3513.3514.3515.35
kmin3.755.256.77.78.79.6511.6512.6513.6514.65
smax+nominal size10131719222427303236
smin9.412.316.318.221.223.226.229.23135
Metric Bolt Sizes

Metric Carriage Bolt Sizes

Carriage bolts are an application-specific fastener designed for use in carpentry, wood based materials, and the construction of wood products. They get their name from their original purpose, which was in the construction of carriages and carriage wheels back in the early 1800s. Carriage bolts are a type of hexagon bolt specialized for use in woodworking, in particular, fastening metal to wood. Carriage bolts are designed with a domed head, which can prevent loosening from one side, an enlarged head shape also prevents the bolt from being pulled through a wooden construction, below is Metric Carriage Bolt sizes and charts

Metric Bolt Sizes
Screw Thread(d)M6M8M10M12M16M20
PPitch11.251.51.7522.5
bL<125182226303846
b125<L<2004452
dkmax14.21822.326.63543
dsmax6810121620
emin7.6410.212.815.3720.5725.73
K1max334455
K1min2.42.43.23.24.24.2
Kmax3.64.85.86.88.910.9
kmin3456810
smax6.488.5810.5812.716.720.84
smin5.887.859.8511.8215.8219.79
Metric Bolt Sizes

Slotted countersunk head Bolt Screw Sizes

Countersunk Bolts are flat-headed bolt fasteners with hex socket drive into the head. Countersunk bolts have a cone-type neck with flat head. Flat Head Hex Socket Bolts, Flat Head Socket Cap Bolts are other alias of hex head bolts. used when a smooth surface is required. Common applications include bridge decking, walkways, and railing

Metric Bolt Sizes
Screw Thread(d)M10M12M16M20M22M24
PPitch1.51.7522.52.53
amax80° 80° 80° 65° 65° 65°
amin 75° 75° 75° 60° 60° 60°
dkmax+nominal size172128323538
dkmin16.5720.4827.4831.3834.3837.38
kNominal Size5.57911.51213
kmin5.266.718.7111.1511.6512.65
kmax5.747.299.2911.8512.3513.35
nmin+nominal size2.534555
nmax2.753.254.35.35.35.3
t344456
Metric Bolt Sizes

Eye Bolts Sizes

Eyebolt consists of a threaded shank with a ring or loop at one end, often used to attach an eye to a structure, through which ropes, cables, or shackles can be secured, Eye bolts can be used as a connection point for rigging, anchoring, pulling, pushing, or hoisting applications. Although eye bolts are commonly used in industrial applications, they’re also commonly misunderstood or used incorrectly.

Metric Bolt Sizes
Screw Size(d)M5M6M8M10M12M16M20M24M27M30M33M36M39
Ppitch0.811.251.51.7522.5333.53.544
bL<1251618222630384654606
b125<L<2002832364452606672788490
bL>2004957657379859197103
d1max5.036.038.03610.03612.04316.04318.04322.05224.05227.05230.05233.06236.062
d1min56810121618222427303336
dkTpye A,Tpye A(max)12141820253240455055606570
dkTypeA(min)10.912.916.918.723.730.438.443.448.453.158.163.168.1
dkTpye B and C(min)11.5713.5717.5719.4824.4831.3839.3844.3849.3854.2659.2964.2669.26
STpyeA(max)891114171924283034384146
smin7.528.5210.313.316.318.1623.1627.1629.1633374045
sTpye B and C(max)67912141722252730343841
smin5.886.858.8511.8213.8216.8221.7924.7926.7929.7933.7537.7540.75
Metric Bolt Sizes

Metric T Bolt Sizes

 T bolt is a bolt having a crosspiece for a head. a bolt with a head of square or rectangular shape intended to fit a T slot.T-slot screws and T-slot nuts are used on aluminum profile slots and on machine tables to enable threaded connections along T-nuts.below is Metric T bolt sizes

Metric Bolt Sizes
Thread Size(d)M24M30M36M42M48M56M64M72M80M90M100
Pitch33.544.555.566666
b100120140170200220240260290320350
k11820253030303030303030
k1822253035405055607075
s124303642485664728090100
s65758595110125140155170185205
r(min)1.61.6222334445
Metric Bolt Sizes

Metric U Bolt Sizes

A U-bolt is in the shape of the letter “U” with threads on both ends, U bolt is also named a U-shaped bolt, a U bolt clamp, or U bolt bracelet. Due to the excellent performance and low price, the U bolt is a superb steel fastener throughout the industry.typically used to support pipework or to attach a part to a pole, beam or wall, where the “u” shape keeps it firmly in place, adding stability to the support,below is Metric U Bolt Sizes

Metric Bolt Sizes
Size56.5810121416192226303440
a12141820242832364046546068
b13172024283135364050556065
d1M5M6M8M8M10M12M14M14M16M20M20M22M24
h1253241465666768396118131150167
Metric Bolt Sizes

Metric 12 Point Flange Bolt Sizes

The driver of a 12-point screw uses two overlapped hexagon shapes, creating 12-points and a flanged underside. These are also referred to as ferry cap screws or 12 point flange screws.12-Point Bolts are an alternative head design for hex socket cap screws. The flange diameter and head height are designed to fit a range of applications and counterbored holes designed for standard hex socket cap screws.Below is a Metric flange bot sizes

Metric Bolt Sizes

Metric Wheel Bolt Sizes

Wheel studs are the threaded fasteners that hold on the wheels of many automobiles. They are semi-permanently mounted directly to the vehicle hub, usually through the brake drum or brake disk. Lug nuts are fastened onto the wheel stud to secure the wheel.Wheel bolts are standard on many German-built cars, and use a threaded stem attached to a tapered head that matches to the wheel insert. The bolt goes from the wheel, through the brake rotor hat, straight into the hub, locking everything in place.The wheels are mounted using lugs, which are screwed onto the stud,below is metric wheel bolt sizes

Metric Bolt Sizes
Screw Thread(D)M16M18M16M18M20M20M30
d1M16M18M16M18M20M20M30
P1.51.51.51.51.51.51.5
ds ≈ 15151717191929
ds1 ≈ 16181618202222
dk26262626303030
s20202020242424
b25252727313130
b116181618202222
k4.54.54.54.5555
R1(MIN2222333
R20.5~1.00.5~1.00.5~1.00.5~1.00.5~1.00.5~1.00.5~1.0
Metric Bolt Sizes

Metric Shoulder Screw Sizes

Shoulder screws, or shoulder bolts, are machine screws that have an unthreaded shoulder under the head that is larger in diameter than the threads. It is this enlarged shoulder that determines the nominal size of the screw. Much like all other screws, shoulder screws are meant to hold objects together and in a particular position. However, these screws are designed for use in parts that require a mounting pin, joint, shaft, dowel, pivot, or sliding motion. below is metric shoulder screw sizes

Metric Shouder Bolt Sizes
dsNom681012162024
max5.997.9879.98711.98415.98419.98023.98
min5.967.9519.95111.94115.94119.92823.928
dM5M6M8M10M12M16M20
pitchp0.811.251.51.7522.5
bmax9.7511.2513.2516.418.422.4027.40
min9.2510.7512.7515.617.6021.6026.60
dkmax10.2213.2716.2718.2724.3330.3336.39
min9.7812.7315.7317.7323.6729.6735.61
kmax4.55.579111416
min4.326.326.788.7810.7313.7315.73
sNom345681012
max3.084.0955.0956.0958.11510.11512.142
nin3.024.025.026.028.02510.02512.032
tmin2.43.34.24.96.68.810
Metric Bolt Sizes

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