Machine Screws

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Lag Screws

Hex Head Lag Screws


Description:

Hex head lag screws from ITA Fasteners are screws used on tough timbers and hence, often knows as one of the toughest non-industrial screws. They can be used for fastening dense timbers with other dense timbers or thin metals. The screws come in a huge size, with a length of one inch and a thickness of quarter inch. In addition to this, they have coarse threads which do not run the entire length of the screw. These screws require a pilot hole to be drilled before being drilled into place. It is advisable to use a nut to secure the fastening in place.

Due to the sheer size and strength of these screws, they can handle heavy duty applications with ease. Since the impact of the screws on the surface can be huge, all the components which need to be assembled have to be aligned before using the screws. It is impossible to disassemble a structure once it has been fastened using lag screws. It is available in stainless steel, carbon steel, and alloy steel to bear more wear and tear while also making it more corrosion resistant.


Dimensional Standards:

DIN 571


Size range:

Metric:
Inches:

LAG SCREW

Lag Screw Dimensions
Nominal SizeThreadsHead Width Head
perAcrossAcrossHeight
InchFlatsCorners 
FractionDecimalBasicAvgBasic
01/Apr0.251007/1601/Feb11/64
05/160.3125901/Feb09/1607/32
03/Aug0.375709/1641/6401/Apr
7/16†0.4375705/Aug45/6419/64
01/Feb0.5603/Apr27/3211/32
05/Aug0.625515/161 1/1627/64
03/Apr0.754 1/21 1/81 17/6401/Feb

Table 1. Lag Screw Dimensions. Nominal size in fractional and decimal inches, threads per inch, and head width across flats and corners and head height, in inches. (Note: Average size is calculated and rounded to nearest 64th.) † 7/16" is not commonly available.

Lag Screw Pilot Hole Sizes
Screw SizePilot Hole Size
BodyThreaded Section
Soft WoodMedium WoodHard Wood
Groups III & IVGroup IIGroup I
01/Apr01/Apr03/3205/3203/16
05/1605/1609/6403/1613/64
03/Aug03/Aug11/6415/6401/Apr
7/16†07/1613/6409/3219/64
01/Feb01/Feb15/6405/1611/32
05/Aug05/Aug05/1613/3229/64
03/Apr03/Apr13/3201/Feb09/16

Table 2. Lag Screw Pilot Hole Sizes. Unthreaded body and threaded section pilot hole sizes, in inches, for soft, medium and hard wood. See a table of Species Groups for Sawn Lumber for a listing of species in each group. † 7/16" is not commonly available.

DIN 571 - Hex wood screws

Equivalent norms: CSN 21810; PN 82501; UNI 704;

DIN 571 - Hex wood screws dimensions

Legend:
b - length of the thread (at least)
l - length of bolt
k - head height
e - the diameter of the circumscribed circle (not less than)
s - size hex head turnkey
Makings:
Steel: steel
Stainless: A2, A4
Plastic: - 
Non Ferrous: -
Thread: as DIN 7998
Notes:
Table according to DIN 571:
dimensions in mm

Thread456-7810121620
dsnominal size max.4567810121620
min.3,524,525,526,427,429,4211,315,319,3
damax.567,28,210,212,215,219,224,4
knominal size2,83,5455,5781013
max.3,13,884,385,385,887,458,4510,4513,9
min.2,53,133,634,635,136,557,559,5512,1
snominal size7810121317192430
max.7810121317192430
min.6,647,649,6411,5712,5716,5718,4823,1629,16
emin.7,58,6310,8913,0714,218,7220,8826,1732,95
lweight kg/1000pcs
nominal sizemin.max.
1615,116,91,71292       
2018,9521,052,013,425,02      
2523,9526,052,414,025,82 11,5    
3028,9531,052,814,626,62 12,923,6   
3533,7536,253,115,127,42 14,225,836,2  
4038,7541,253,515,828,22 15,62839,2  
4543,7546,25  8,94 16,93042,1  
5048,7551,25  9,64 18,232,145,484,1 
5553,556,5  10,5 19,634,348,689,7 
6058,561,5  11,2 20,936,551,894,9165
6563,566,5    22,238,554,799,5174
7068,571,5    23,640,757,8107182
7573,576,5    2542,961112192
8078,581,5    26,545,264,5118201
9088,2591,75    29,449,971130220
10098,25101,75    325477,1141238
110108,25111,75      83,4152253
120118,25121,75      89,5163275
130128132       175293
140138142       187317
150148152       198328
160158162       209348
170168172        366
180178182        385
190187,7192,3        404
200197,7202,3        421

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