*
STANDARD LENGTH TOLERANCES FOR
CABLE ASSEMBLIES AND CUT-LENGTH CABLE
Liberal
tolerances allow a faster rate of production and lower cost. The "standard"
tolerances shown in the chart normally permit a cost saving over "close"
tolerances. Tolerances closer than those shown can be supplied at a higher
cost upon (1) reviewing your specific requirements and (2) mutual agreement
regarding methods of inspection.
Length in
Feet
|
Tolerance
in Inches Standard
|
0-5
5-10
10-20
|
±1/8
±3/16
±1/4
|
20-40
40-60
60-90
|
±3/8
±1/2
± 1
|
90-200
Over 200
|
± 2
± 4
|
* CABLE
DIAMETER RELATED TO PULLEY OR SHEAVE DIAMETER
Cable or wire rope will give increased service if (1)
it operates over the largest possible pulley or sheave diameter and (2)
it is properly supported in the pulley or sheave groove. Working life
of the individual wire strands is greatly reduced as the pulley or sheave
diameter is diminished. The chart shows minimum tread diameters over which
various sizes and constructions of cable should operate.
When designing
a pulley groove, the groove should be 150% of the maximum tolerance of
the wire rope.
* EXAMPLE:
A 1/8" 7 x
19 aircraft cable has a minimum tolerance of .014" (.125 minimum,
.139 maximum). Multiplying the .014" maximum tolerance by 150% =
.021". Adding .021" to 139" maximum diameter = .160" which should
be the pulley groove dimension.
|
*
OUTSIDE-DIAMETER TOLERANCES FOR
PLASTIC COATED CABLE
Inner
Cable Diameter
in Inches |
Coated
to
Outside-Diameter
in Inches |
Standard
Tolerance
Of O.D. in Inches |
3/64
to 1/8 |
up
to 1/4 max. |
±
.007 |
5/32
to 1/4 |
up
to 3/8 max |
±
.010 |
9/32
to 3/8 |
up
to 1/2 max |
±
.015 |
7/16
to 1/2 |
up
to 3/4 max. |
±
.020 |
MINIMUM
TREAD DIAMETER
FOR PULLEYS OR SHEAVES |
Ratio
of cable diameter to pulley diameter: |
|
42:1 |
24:1 |
12:1 |
28:1 |
18:1 |
| Desirable
Minimum in Inches / Critical Minimum in Inches |
Cable
Diameter In Inches |
6
x 7
or
7 x 7 |
6
x 19
or
7 x 19 |
6
x 31
7 x 31
6 x 37 |
6
x 7
or
7 x 7 |
6
x 19
or
7 x 19 |
1/16
3/32
1/8 |
2-5/8
2-15/16
5-1/4 |
-
2-1/4
3 |
-
-
- |
-
1-11/16
2-1/4 |
-
-
- |
5/32
3/16
7/32 |
6-9/16
7-7/8
9-3/16 |
3-3/4
4-1/2
5-1/4 |
-
-
- |
2-7/8
3-3/8
4 |
-
-
- |
1/4
5/16
3/8 |
10-1/2
13-1/8
15-3/4 |
6
7-1/2
9 |
3
3-3/4
4-1/2 |
4-1/2
5-5/8
6-3/4 |
2-1/2
3-1/8
3-3/4 |
7/16
1/2 |
18-3/8
21 |
10-1/2
12 |
5-1/4
6 |
7-7/8
9 |
4-3/8
5 |
When designing aircraft control cable systems, minimum ratio of cable diameter
to pulley diameter is 35:1.
Pre-stretched aircraft cable, both stainless steel and galvanized, are available
in 1/16 ", 3/32" and 1/8" diameter at 10% added charge.
|