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Self Tapping Screws

A self-tapping screw is a screw that can tap its own hole as it is driven into the material. Self-tapping screws come with a sharp, piercing tip or a flat, blunt tip. More narrowly, self-tapping is used only to describe a specific type of thread-cutting screw intended to produce a thread in relatively soft material or sheet materials, excluding wood screws.
The sharp-tipped screws are designed for drilling their own hole into softer materials such as wood and plastic so they don't need a pilot hole. Other specific types of self-tapping screws include self-drilling screws and thread rolling screws. The advantage of the flat-tipped screw is that it won't get stuck in the material and break off. For hard substrates such as metal or hard plastics, the self-tapping ability is often created by cutting a gap in the continuity of the thread on the screw, generating a flute and cutting edge similar to those on a tap. For softer substrates such as wood or soft plastics, the self-tapping ability can come simply from a tip that tapers to a gimlet point (in which no flute is needed). Like the tip of a nail or gimlet, such a point forms the hole by displacement of the surrounding material rather than any chip-forming drilling/cutting/evacuating action.







COUNTERSUNK HEAD - SLOTTED  - DIN 7972


d1 2.2 2.9 3.5 3.9 4.2 4.8 5.5 6.3
d2 max 4.3 5.5 6.8 7.5 8.1 9.5 10.8 12.4
k max 1.3 1.7 2.1 2.3 2.5 3 3.4 3.8
n 0.6 0.8 1 1 1.2 1.2 1.6 1.6
t min. 0.4 0.5 0.6 0.7 0.75 0.85 1 1.2


Metric Series Approx Count Per 50kg.
Dia 2.2 2.9 3.5 3.9 4.2 4.8 5.5 6.3
Length
6.5mm 357143 206612            
9.5mm 250000 142857 91241 58275 64516 45455    
13mm 185185 105042 69252 56818 49020 34483 23697 19763
16mm 151515 85616 57405 46729 40650 28571 17241 16287
19mm   72254 49020 39683 34722 24390 17422 13850
22mm     42735 34483 30303 21277 15337 12048
25mm     37879 30488 26882 18868 13699 10661
32mm         21277 14925 10965 8403
38mm           12658 9363 7112


PAN HEAD - SLOTTED  - DIN 7971


d1 2.2 2.9 3.5 3.9 4.2 4.8 5.5 6.3
d2 max 4.2 5.6 6.9 7.5 8.2 9.5 10.8 12.5
k max 1.35 1.75 2.1 2.25 2.45 2.8 3.2 3.65
n 0.6 0.8 2 1 1.2 1.2 1.6 1.6
t min. 0.55 0.75 0.95 1.05 1.15 1.35 1.55 1.8


Metric Series Approx Count Per 50kg.
Dia 2.2 2.9 3.5 3.9 4.2 4.8 5.5 6.3
Length
4.5mm 287356              
6.5mm 233645 117925            
9.5mm 182482 93985 59524 46729 39683 27027    
13mm 123762 75988 49020 38760 33333 22936 15432 11574
16mm   65274 42735 33784 29240 20161 13812 10288
19mm   57208 37879 29940 26042 18248 12500 9259
22mm     34014 26882 23474 16556 11416 8418
25mm     30864 24390 21368 15152 10504 7716
32mm         17668 12626 8818 6460
38mm           11062 7752 5669


COUNTERSUNK HEAD - SLOTTED - DIN 7982


d1 2.2 2.9 3.5 3.9 4.2 4.8 5.5 6.3
d2 max 4.3 5.5 6.8 7.5 8.1 9.5 10.8 12.4
k max 1.3 1.7 2.1 2.3 2.5 3 3.4 3.8
Cross Recessed 1 1 2 2 2 2 3 3
m 2.5 3 4.2 4.6 4.7 5.1 6.8 7.1


Metric Series Approx Count Per 50kg.
Dia 2.2 2.9 3.5 3.9 4.2 4.8 5.5 6.3
Length
4.5mm 500000              
6.5mm 357143 178571            
9.5mm 250000 142857 92593 75758        
13mm 185185 105042 69638 56818 49020 34483    
16mm 151515 85616 57405 46729 40650 28571 20080 16287
19mm   72254 49020 39683 34722 24390 17422 13850
22mm     42735 34483 30303 21277 15337 12048
25mm     37879 30488 26882 18868 13699 10661
32mm         21277 14925 10965 8403
38mm             9208 7112


PAN HEAD - SLOTTED - DIN 7981



d1 2.2 2.9 3.5 3.9 4.2 4.8 5.5 6.3
d2 max 4.2 5.6 6.9 7.5 8.2 9.5 10.8 12.5
k max 1.8 2.2 2.6 2.8 3.05 3.55 3.95 4.55
Cross Recessed 1 1 2 2 2 2 3 3
m 2.6 3 4.2 4.4 4.6 5 6.5 7.1



Metric Series Approx Count Per 50kg.
Dia 2.2 2.9 3.5 3.9 4.2 4.8 5.5 6.3
Length
4.5mm 312500              
6.5mm 250000 125000            
9.5mm 192308 98039 63291 47619 40984 27027    
13mm 151515 79365 51546 39370 34247 22727 15625 12821
16mm 128205 67568 44643 34247 29940 20000 13889 11261
19mm   58824 39370 30303 26596 17857 12500 10040
22mm     35211 27174 23810 16129 11416 9058
25mm     31847 24631 21739 14706 10504 8251
32mm         17857 12195 8818 6831
38mm           10638 7752 5952