Springs - Boing Boing Boing - rates in different measures
N/mm
Kg/mm
lbs/inch
notes
3.33
0.34
19.0

3.53
0.36
20.2

3.73
0.38
21.3

3.92
0.40
22.4

4.60
0.47
26.3

6
.611
34.3
 
8
.815
45.7
 
10
1.019
57
 
12
1.22
69
 
14
1.43
80
 
16
1.63
94
 
18
1.84
103
 
20
2.04
114
 
21
2.14
120
 
22
2.24
125
 
23
2.35
132
 
24
2.45
137
 
25
2.55
143
 
26
2.65
149
 
28
2.85
160
 
30
3.06
171
 
32
3.26
183
 
34
3.46
194
 
36
3.67
206
 
38
3.87
217
 
40
4.08
228
 
42
4.28
240
 
44
4.48
251
 
46
4.69
263
 
48
4.89
274
 
50
5.10
286
 
52
5.30
297
 
54
5.50
308
 
56
5.71
320
 
58
5.91
331
 
60
6.11
343
 
62
6.32
354
 
64
6.52
365
 
66
6.73
377
 
68
6.93
388
 
70
7.13
400
 
75
7.64
428
 
80
8.15
457
 
85
8.66
485
 
90
9.17
514
 
95
9.68
542
 
100
10.19
571
 
105
10.70
600
 
110
11.21
628
 

what is a Newton?, what is an mm?, what is a Kg?, what is an inch?, what is a lbs?
mm = millimeter

Kg = kilogram = 1000 grams
1.0 newton/mm(N/mm) = 5.710148 pound/inch(lb/in)
1.0 newton(N) = .1019716 Kg
1.0 newton/mm(N/mm) = .1019716 Kg/mm
1.0 lb/in = .1751268 newton/mm(N/mm)
dyne = 100,000 newtons
the following symbols are used in spring equations -
AC = Active coils
CL = compressed length
D = mean coil diameter=OD-d
d =  diameter of wire
E = modulus of elasticity
FL = Free length, unloaded spring
N = number of active coils
P = load
TC = total coils
SH = solid height
p = pitch

formulas for compression springs, closed and ground ends -
SH = TCxd
N = TC-2 or (FL-2d)/p
FL = (pxN)+2d
TC = ((FL-2d)/2)+P

i figured if you had a lot of time to waste, you could run calculations on springs, until you were totally confused. have fun!