Related Resources: hardware

Pilot Holes Asbestos Fiberglass Compositions with Self Tapping Screws

ANSI Hardware Design and Application Guide
ISO Metric Hardware Engineering and Design Data
Fastener and Screw / Bolt Design, Formula & Calculations

Approximate Pilot Holes In Asbestos or Fiberglass Compositions for Type A Steel Sheet Metal Thread Forming Screws

Pilot Holes In Asbestos or Fiberglass Compositions

In Fiberglass or Asbestos Compositions
Screw
Size
Hole
Size
Drill
Size
Min. Mat'l
Thickness
Penetration in
Blind Holes
Min.
Max.
4
0.094
42
0.188
0.250
0.750
6
0.106
36
0.188
0.250
0.750
7
0.125
1⁄8
0.250
0.312
0.750
8
0.136
29
0.250
0.312
0.750
10
0.161
20
0.312
0.375
1.000
12
0.185
13
0.312
0.375
1.000
14
0.213
3
0.438
0.500
1.000

Type A is not recommended, use Type AB. See footnote at bottom of

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