Nails and Spikes - Withdrawal Force

Calculate the allowable withdrawal load or force for a nail or spike driven into wood using the formula F = 1380 × SG^(5/2) × D. Includes both imperial and metric calculators with reference data tables for common US and metric wire nails.

Nails and Spikes - Withdrawal Force Calculator

Allowable withdrawal load or force for a common nail or spike driven into side grain perpendicular to the fibers of seasoned wood can be estimated using:

F = 1380 × SG^(5/2) × D

Where:

F = Allowable withdrawal load or force per inch of penetration (lb/in)
SG = Specific gravity of oven dry wood
D = Diameter of nail or spike (inches)

Note: The allowable load is 1/5 of the ultimate withdrawal resistance.

Calculator

Inputs

Specific Gravity (SG) - Oven Dry Wood

Diameter of Nail (inches) (in)

Penetration Depth (inches) (in)

Results

Withdrawal Force per Inch-- lb/in

Total Withdrawal Force-- lb

Calculator

Inputs

Specific Gravity (SG) - Oven Dry Wood

Diameter of Nail (mm) (mm)

Penetration Depth (mm) (mm)

Results

Withdrawal Force per mm-- N/mm

Total Withdrawal Force-- N

Size	Length (in)	Allowable Withdrawal Force (lb)
2d	1	17.6
3d	1.25	25.3
4d	1.5	39.9
5d	1.75	46.5
6d	2	58.5
8d	2.5	81.7
10d	3	108
12d	3.25	117
16d	3.5	141
20d	4	198
30d	4.5	242
40d	5	290
60d	6	348

Length (mm)	Diameter (mm)	Allowable Withdrawal Force (N)
20	1.2	40.4
25	1.4	58.9
30	1.6	80.8
35	1.6	94.2
35	1.8	106
40	2.0	135
45	2.2	167
50	2.2	185
55	2.2	204
55	2.5	231
60	2.5	252
60	2.8	283
65	2.8	306
65	3.1	339
70	3.1	365
80	3.1	417
80	3.4	458
90	3.4	515
90	3.8	575
100	3.8	639
100	4.2	707

Nails and Spikes - Withdrawal Force | MEPKit Engineering Tools | MEPKit