Rope Data
Flexibility
Apart from Locked Coil & specialised constructions too complicated to detail here, our standard constructions in their approximate order of flexibility are :
Construction 
For 26mm Diameter Rope 
Strands 
Construction 
Outer Wire diameter 
% of solid bar 
6x7 
(6/1) 
2.75 mm 
47 
6x8 
(7/s) 
2.75 mm 
57 
6x15 
(7/7/1) 
2.50 mm 
49 
6x17 
(8/8/1) 
2.26 mm 
49 
6x22 
(9/12/s) 
2.26 mm 
56 
6x23 
(10/12/s) 
2.11 mm 
56 
6x19 
(9/9/1) 
2.05 mm 
49 
6x21 
(10/5+5F/1) 
1.90 mm 
50 
6x19 
(6&6/6/1) 
1.84 mm 
50 
6x12 
(12/Fibre) 
1.66 mm 
29.5 
6x25 
(12/12/s) 
1.64 mm 
56 
6x19 
(12/6+6F/1) 
1.64 mm 
50 
6x19 
(12/6/1) 
1.64 mm 
45.5 
17x7 
(6/1) 
1.64 mm 
52 
8x19 
(9/9/1) 
1.63 mm 
43.5 
6x24 
(15/9/Fibre) 
1.54 mm 
41 
6x28 
(15/12/s) 
1.53 mm 
56 
6x36 
(14/7&7/7/1) 
1.44 mm 
50 
6x37 
(15/15/6/1) 
1.40 mm 
50 
6x29 
(17/11/s) 
1.37 mm 
56 
8x19 
(12/6+6F/1) 
1.31 mm 
44.5 
6x41 
(16/8&8/8/1) 
1.28 mm 
50 
34x7 
(6/1) 
1.23 mm 
53 
6x37 
(18/12/6/1) 
1.18 mm 
45.5 
6x61 
(24/18/12/6/1) 
0.92 mm 
45.5 
Rope Calculations
The following section contains calculations, which use the symbols detailed below.
Symbols used in Formulae 
Units 
WT = Total load 
Kgf 
WS = Static load 
Kgf 
WD = Dynamic load 
Kgf 
WB = Bending load 
Kgf 
WR = Suspended rope
weight
(unit rope weight x rope length) 
Kgf 
WL = Rope end load 
Kg 
g = Acceleration due to
gravity 
m/s^{2
}(9,81 m/s^{2}) 
a = System acceleration 
m/s^{2} 
x = Elastic stretch 
mm 
d = Rope diameter 
mm 
E = Apparent Modulus of Elasticity 
Kgflmm^{2} 
A = Nominal Cross
sectional area of rope 
mm^{2} 
L = Rope length 
m 
Stretch
Two types of stretch occur. Constructional (or permanent stretch) and Elastic Stretch (or load stretch)
Constructional Stretch
This occurs due to the wires within the rope bedding in. The rate and degree of constructional stretch varies accordingly to the type of rope, how heavily and how often it is loaded and how much it is bent.
Any rope will tend to stretch more when it is new. The rate of stretch will decrease throughout its useful life, although the rate of stretch might increase again as the rope starts to wear out at the end of its life.
Total constructional stretch is difficult to predict. The tables below offers a guide as to what should be expected.
Stranded Ropes
Fibre Core

Load 
Typical F of S 
% Stretch 
Light 
10 : 1 
0.25 
Medium 
5 : 1 
0.50 
Heavy 
3 : 1 
0.75 

Steel Core 
As above ½ 
Many bends 
As above x2 
Single Strand Ropes
(Locked Coil, Spiral Strand, etc)
These generally stretch 0.25% in total.
Reducing Constructional Stretch  Prestressing and Prestretching
By cyclically loading any rope, the above constructional stretch can be reduced and in some cases almost eliminated. By removing the construction stretch and applying the working load to the rope, accurate measurements can be marked onto the rope to enable accurate fixing of terminations either before or after installation. Latch & Batchelor are able to offer this service. Please contact our Technical Department for more details.
Elastic Stretch
This is stretch induced by a change in rope end load. A reasonably accurate guide to elastic stretch can be calculated from:
x = WL x 103 EA
The rope will increase in length by x when the load W is applied and decrease in length by x when the load W is removed.
Apparent Modulus of Elasticity  E
Ropes are not truly elastic, but can be regarded as so when applied loads are within normally accepted ranges.
Values for E for various constructions of rope are listed below.
They are for guidance only.

Apparent Modulus of Elasticity (Kgslmm2) 
6 x 7 Fibre Core 
6300 
6 x 7 Steel Core 
7000 
6 x 19 Fibre Core 
6000 
6 x 19 Steel Core 
6500 
6 x 36 Fibre Core 
5500 
6 x 36 Steel Core 
6000 
Multistrand ropes 
5500 
1 x 7, 1 x 19, 1 x 36 
10000 
Locked Coil Hoist 
10000 
Half Locked Guide 
12500 
Spiral Strand 
12500 
Calculation of Rope Loads
Static Load
Usually used when considering factors of safety, tread pressures, etc.
Static Load = weight of suspended rope + weight of rope end load
(conveyance, payload, attachments, etc)
WS = WR + WL
Factor of Safety = Minimum breaking load/Static load
FOS = (MBL ÷ WS)
Dynamic Load
This is the increased value of the static load due to acceleration. As the rope is elastic, the rope end load may oscillate, increasing the rate of acceleration. A factor of 1.5 is therefore applied to the Mean rate of acceleration to account for this :
Dynamic load = Static load x 1.5 x rate of acceleration / gravitational constant
WD = (WS x 1.5 x a ) ÷ g
Bending Load
This is the additional load induced in the outer wires of the rope as they are bent over a sheave or drum. This load increases with outer wire diameter but decreases with larger drum or sheave diameters,
Bending Load = Outer Wire Dia x Cross Section of Rope Area x Apparent Modulus of Elasticity ÷ Drum or sheave dia
WB = (d x A x E) ÷ D
where E is obtained from values on Page, A is the nominal cross sectional area of the rope
A = x (rope diameter
^{2}) ÷ 4
Total Load
This is used as a guide to help choose suitable ropes or design suitable winding systems. Experience has shown that if the total load is over 25% of the actual breaking load of a rope, it is likely to suffer premature fatigue of the wires within the rope.
Therefore as a guide to achieve a satisfactory fatigue life :
Total Load = (x 100 < 25) ÷ Breaking Load
This, of course, does not take into account the effects of wear, corrosion and other factors that can affect fatigue and rope life.
Total Load = Static Load + Dynamic Load + Bending Load
WT = WS + WD + WB
Recommended Minimum Drum and Pulley Diameters

Rope 
Drum 
Locked Coil Winding Rope 
1 
120 
Haulage Rope 
1 
60 
Engineering Rope 6x19 
1 
24 
Engineering Rope 6x24 & 17x7 
1 
22 
Engineering Rope 6x37 & 34x7 
1 
19 
Lift Ropes 6x12/6 x 6/1 
1 
40 
Lift Ropes 8x9/9/1 


Lift Ropes 6x9/9/1 
1 
47 
General Engineering Data
Manufacturing Tolerances
Rope Diameter : 
Engineering ropes: 
+4% / +5% 
Lift ropes 
 up to
10mm dia. Incl. 
+6% / 2% (+4% / 0%
at 10% MBL) 

over 10mm dia. 
+5% / 2% (+3% / 0%
at 10% MBL) 
Small ropes: 

2 & 3 mm dia. 
+7% / 1% 

4 & 5 mm dia. 
+6% / 1% 

6 & 7 mm dia 
+5% / 1% 
Rope length: 

up to and Incl. 400m 
+5% / 0% 

over 400m 
+20% m for each 1000m
or part thereof 0% 

Locked Coil Ropes 
Refer to British Coal
Specifications 
Conversion Factors
Length 
in 
x 
25.4 
= 
mm 
x 
0.03937 
= 
in 
ft 
x 
0.3048 
= 
m 
x 
3.28 
= 
ft 
mile 
x 
1.60934 
= 
Km 
x 
0.62137 
= 
mile 
Area 
in^{2} 
x 
645.16 
= 
mm^{2} 
x 
0.00155 
= 
in^{2} 
ft^{2} 
x 
0.0929 
= 
m^{2} 
x 
10.7639 
= 
ft^{2} 
Volume 
in^{3} 
x 
16.387 
= 
cm^{3} 
x 
0.06102 
= 
in^{3} 
ft^{3} 
x 
0.028317 
= 
m^{3} 
x 
35.3147 
= 
ft^{3} 
ft^{3} 
x 
28.3161 
= 
litre 
x 
0.035316 
= 
ft^{3} 
Mass 
lb 
x 
0.453592 
= 
Kg 
x 
2.20462 
= 
lb 
UK ton 
x 
1.01605 
= 
tonne 
x 
0.984207 
= 
UK ton 
lb/ft 
x 
1.488 
= 
Kg/m 
x 
0.672 
= 
lb/ft 
Force 
lbf 
x 
0.453592 
= 
Kgf 
x 
2.20462 
= 
lbf 
Kgf 
x 
9.80665 
= 
N 
x 
0.101972 
= 
Kgf 
UK tonf 
x 
9.96402 
= 
kN 
x 
0.100361 
= 
UK tonf 
Stress 
Kgf/mm^{2} 
x 
9.80665 
= 
N/mm^{2} 
x 
0.101972 
= 
Kgf/mm^{2} 
lbf/in^{2} 
x 
0.00689476 
= 
N/mm^{2} 
x 
145.04 
= 
lbf/in^{2} 
tonf/in^{2} 
x 
1.57488 
= 
Kgf/mm^{2} 
x 
0.634969 
= 
tonf/in^{2} 
hbar 
x 
0.1 
= 
N/mm^{2} 
x 
10.0 
= 
hbar 
MPa 
x 
1.0 
= 
N/mm^{2} 

Relevant Specifications
References have been made to various specification where breaking loads, weights etc apply.
Only relative items are quoted, for full details reference should be made to the appropriate standard.
British Standards
Number 
Date 
Title 
236 
1968 
Stranded wire ropes for
mine hoisting 
302 
1987 
Stranded steel wire
ropes 
443 
1982 
Testing zinc coatings
on steel wire 
461 
1970 
Bordeaux connections 
462 
1983 
Wire rope grips 
463 
1958 
Sockets for wire ropes 
464 
1958 
Thimbles for wire rope 
525 
1973 
Fibre cores for wire
ropes 
643 
1970 
White metal ingots for
capping steel wire ropes 
970 
1983 
Part 4: Valve steel 
2763 
1982 
Round carbon steel wire
for wire ropes 
4429 
1987 
Rigging screws and turn
buckles for general engineering, lifting
purposes and pipe hanger applications 
5281 
1975 
Ferrule  secured eye
terminations for wire ropes 
6210 
1983 
Safe use of wire rope
slings for general lifting purposes 
6570 
1986 
Selection, care and maintenance
of steel wire ropes 
7035 
1989 
Socketing of stranded
wire rope 
MA29 
1982 
Steel wire rope and
strand for yachts 
British Coal Standards
Number 
Date 
Title 
175 
1968 
Wire
ropes for mineral haulage and manriding 
176 
1968 
Stranded wire ropes
for winding 
186 
1970 
Locked coil winding
ropes 
366 
1968 
Round strand wire
ropes for mineral haulage 
367 
1968 
Triangular strand
wire ropes for mineral haulage 
368 
1968 
Wire ropes for
manriding haulage 
386 
1968 
Wire ropes for use
with coalcutters and other coal face machinery 
388 
1970 
HalfLocked coil
guide rope 
461 
1965 
Sockets, zinc cone
and tail strand units 
International Standards
Number 
Title 
ISO 7595 
Socketing procedures
for wire ropes  Molten Metal 
ISO 7596 
Socketing procedures
for wire ropes  Resin Socketing 
Other Sources Of Reference
Federation of Wire Rope Manufacturers of Great Britain 
Tables of weights and breaking loads for steel wire ropes 
British Coal

Ropeman's Hand Book

British Coal

Guidance for the
resin capping of wire ropes

Latch
& Batchelor Ltd

Guide to Locked
Coil rope repair

Guidance notes on
the capping of steel wire ropes

For more information with reference to specification or products please feel free to
contact us.