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DIN 571

DIN 571 COACH SCREW /HEX HEAD LAG SCREW/WOOD SCREW/MANUFACTURERS INDIA

What is a coach screw

Coach screws are meant for hardwood applications. They come with a square, flange  or hexagonal head and a pointed tip in which the entire length of the screw is externally threaded as well. Their applications are in metal-to-metal or metal-to-sheet fastening. Mostly, they are also used on concrete surfaces for masonry. Coach screws also known as lag screws are large wood screws with tapered stem, large threads and with a sharp point. Bhalla Fasteners manufactures lag screw which are heavy duty screws used in wood applications in USA ,UK ,Poland,Germany .

The pointed end and external threads ensure that the screws do not slip out of position. To reduce the impact of the screws on the wood, it is advisable to use a washer below the head of the coach screw . This also makes it easy for the screws to be removed. It is available in stainless steel, carbon steel, and alloy steel to bear more wear and tear while also making it more corrosion resistant.

Coach screw sizes at Bhalla Fasteners vary from M6 to M20 in dia and upto 150 mm length of coach screw. At Bhalla Fasteners which is the leading manufacturer ,exporter and supplier of coach screw to USA ,UK, Austrailia, Germany  m10x 30 mm coach screw is always available in stock. It is important to use the correct size spanner, wrench or impacts socket When tightening or loosening a coach screw to avoid damaging the head of the screw. The size you require can be determined by measuring across the flat edges of the head and not point to point.

Difference between coach bolts and coach screw

Coach bolts often called as carraige bolts or cup square hex bolts have a round head with a square underside having metric course threads commonly used in construction and timber trades. Coach bolts are typically measured in metric threads using the international standard ISO metric thread size system. Each bolt is measured and given a size which is denoted by a number preceded by the letter 'M'. The outer diameter of the thread (measured in millimetres) is indicated by the number in the system.

Coach Bolts in  terms of strength, the coach bolt timber connection is very strong and sturdy. This is why this method has been used for so many years when creating timber structures and is  proven to create strong connections. Due to their suitability for more heavy-duty applications and their compatibility with larger tooling, coach bolts are generally available in larger sizes. Once installed, they can hold large amounts of weight. For example, a Grade 5 carriage bolt made out of carbon steel has a tensile strength of 120,000psi or 8437 kilogram-force per sqm and a proof load strength of 85,000psi.

Unlike the pozi-countersunk head on normal screw the coach screw has a hex head which is exposed after installation either by hand or impact socket having a more traditional look . Also general screws have dia from 3mm to 6 mm where coach screw has dia of 6,8,10,12,16 mm and coach screw 300 mm in length are used widely in heavy duty applications like gate construction and fencing timber to timber support. The drill size for drilling into the wood is the same as a coach bolt size.

Often the power tool can over tighten the fixing which can damage the timber that’s why a flange head type coach screw which helps to locate the socket into the head head making it far easier to stop driving when you need to increase the area between the timber and the screw providing perfect clamping ability. Bhalla Fasteners coach screws are available in gunny bags ,boxes and packs .

Coach wood screw with a hexagon head goes straight into wood or missionary with the primary use to fasten heavy timber into position like  when installing gates or fences. To avoid the wood from splitting one should always drill a pilot hole for a coach screw. The hole should be 1/2 the coach screw diameter for softwood and approximately 3/4 for hardwood eg using an 16mm diameter coach screw it would be a 8 mm hole for softwood and 12mm hole for hardwood. Coach screw when fixed into timber we advise using a flat washer or square plate washer with a coach screw to avoid accidental breaking the screw head . A plastic plug can also be used when fixing in the masonary.

Coach screw manufacturers in India

Bhalla Fasteners are top quality nut bolt manufacturer in Ludhiana. Produced with high precision and accuracy, the products are available for supply in USA. Bright zinc plated or yellow passivation is standard plating on coach screw for internal operations but for external environments they are also salt spray tested over 450 hours.

Steel Grades as per coach screw dwg

4.6,5.6,6.8,10.9,12.9
Finish Self, Black, Zinc electroplating, Hot dip galvanised, cadmium,chromate, Green passivation

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Weight Table

COACH SCREW

DIN 571

COACH SCREW DIN 571

coach screw din 571 dimensions
THREAD 4 5 6 -7 8 10 12 16 20
ds nominal size max. 4 5 6 7 8 10 12 16 20
min. 3.52 4.52 5.52 6.42 7.42 9.42 11.3 15.3 19.3
da max. 5 6 7.2 8.2 10.2 12.2 15.2 19.2 24.4
k nominal size 2.8 3.5 4 5 5.5 7 8 10 13
max. 3.1 3.88 4.38 5.38 5.88 7.45 8.45 10.45 13.9
min. 2.5 3.13 3.63 4.63 5.13 6.55 7.55 9.55 12.1
s nominal size 7 8 10 12 13 17 19 24 30
max. 7 8 10 12 13 17 19 24 30
min. 6.64 7.64 9.64 11.57 12.57 16.57 18.48 23.16 29.16
e min. 7.5 8.63 10.89 13.07 14.2 18.72 20.88 26.17 32.95
l weight kg/1000pcs
nominal size min. max.
16 15.1 16.9 1.71 292              
20 18.95 21.05 2.01 3.42 5.02            
25 23.95 26.05 2.41 4.02 5.82   11.5        
30 28.95 31.05 2.81 4.62 6.62   12.9 23.6      
35 33.75 36.25 3.11 5.12 7.42   14.2 25.8 36.2    
40 38.75 41.25 3.51 5.82 8.22   15.6 28 39.2    
45 43.75 46.25     8.94   16.9 30 42.1    
50 48.75 51.25     9.64   18.2 32.1 45.4 84.1  
55 53.5 56.5     10.5   19.6 34.3 48.6 89.7  
60 58.5 61.5     11.2   20.9 36.5 51.8 94.9 165
65 63.5 66.5         22.2 38.5 54.7 99.5 174
70 68.5 71.5         23.6 40.7 57.8 107 182
75 73.5 76.5         25 42.9 61 112 192
80 78.5 81.5         26.5 45.2 64.5 118 201
90 88.25 91.75         29.4 49.9 71 130 220
100 98.25 101.75         32 54 77.1 141 238
110 108.25 111.75             83.4 152 253
120 118.25 121.75             89.5 163 275
130 128 132               175 293
140 138 142               187 317
150 148 152               198 328
160 158 162               209 348
170 168 172                 366
180 178 182                 385
190 187.7 192.3                 404
200 197.7 202.3                 421
Specification Table
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All measurements in millimeters (mm)

d1 s e k
M5 8 8.63 3.5
M6 10 10.89 4
M8 13 14.20 5.5
M10 17 18.72 7
M12 19 20.88 8
M16 24 26.17 10

All information is strictly informative