How Coil Line Layouts are Determined

 

Excessive length may decrease the amount of material stored in the loop. The amount of material stored is equal to the total slack length minus the straight line length. Storage is increased by greater depth not length.

If the material is straightened prior to the loop then the radius of the loop cannot be smaller than the Minimum Bend Radius for the heaviest material that will be run on that line.

Minimum Bend Radius (R min) is the smallest radius that material can be bent into and still spring back flat. If material is bent beyond its (R min), it will retain set and cancel the effect of straightening. (R min) is based on thickness and material strength. For mild steel, (R min)= 360 times material thickness. Commonly, coil lines are set up based on mild steel.

Example: 360 x .080 = 28.8" (R min) x 4 = 115.2 / 12" = 9.6 ft.
                 A feed line height of 57.6" (2 x (R min)) is required to obtain the slack value shown.
 
Loop Length and Slack Available Chart
Height of Feed Above the Floor
Material
Thickness		 36" 48" 60" 72"
Length Slack Length Slack Length Slack Length Slack
0.032 3.8' 56" 3.8' 87" 3.8' 120" 3.8' 155"
0.063 7.3' 31" 7.6' 57" 7.6' 81" 7.6' 105"
0.090 9.6' 27" 10.4' 43" 10.7' 57" 10.8' 88"
0.125 12' 22" 13.2' 35" 14.1' 50" 14.6' 65"
0.156 13.7' 20" 15.3' 31" 16.5' 44" 17.4' 59"
0.187 15.2' 18" 17.1' 28" 18.6' 40" 19.8' 53"
0.212 16.4' 17" 18.5' 26" 20.2' 37" 21.6' 50"
0.250 18' 15" 20.3' 24" 22.3' 34" 24' 45"
0.312 20.3' 13" 23' 21" 25.4' 30" 27.4' 40"
0.375 22.4' 12" 25.6' 19" 28.2' 27" 30.5' 36"
 

Coil weights and Length of Strip

Coil O.D. based on 20” I.D.

36”

42”

48”

54”

60”

66”

72”

Coil Weight per inch of width

190

290

410

540

690

850

1050

Multiply the width of your coil by the weight per inch of width to determine your coil weight.
For weights of metal other than steel, multiply the weight factor above by the following:
Brass: 1.082   Copper: 1.135   Aluminum: .340   Magnesium alloy: .222


Length of Strip on a Coil

                                                     Length of Strip          
                                                       in a coil, in feet     =     Coil Weight per Inch of Width
                                           (based on steel weight)               3.36  X  Stock Thickness
 

Steel Gauge / Decimal Chart

 

Approximate pressure in tons per linear foot
required to make 90 degree air bend in mild steel

 

Thickness

Width of Female Die Opening

Guage

Dec.

1/4

5/16

3/8

1/2

5/8

3/4

7/8

1

1 1/8

1 1/4

1 1/2

2

2 1/2

3

3 1/2

4

5

6

7

8

10

12

20

.036

2.6

2.2

1.6

1.2

1.0

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

18

.048

 

3.5

2.8

2.1

1.7

1.3

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

16

.060

 

 

5.3

3.7

2.8

2.2

1.7

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

14

.075

 

 

 

5.5

4.6

3.5

3.0

2.5

2.1

 

 

 

 

 

 

 

 

 

 

 

 

 

13

.090

 

 

 

 

6.4

5.5

4.3

3.6

3.2

2.8

 

 

 

 

 

 

 

 

 

 

 

 

12

.105

 

 

 

 

9.2

6.9

6.2

5.0

4.3

3.9

3.1

 

 

 

 

 

 

 

 

 

 

 

11

.120

 

 

 

 

 

10.1

8.0

7.0

6.1

5.3

4.3

2.9

 

 

 

 

 

 

 

 

 

 

10

.135

 

 

 

 

 

 

10.3

8.7

7.6

6.9

5.7

3.9

 

 

 

 

 

 

 

 

 

 

9

.150

 

 

 

 

 

 

 

11.9

9.8

8.8

7.0

5.0

3.7

 

 

 

 

 

 

 

 

 

7

.188

 

 

 

 

 

 

 

 

16.9

13.9

11.2

8.3

6.7

4.9

 

 

 

 

 

 

 

 

1/4

.250

 

 

 

 

 

 

 

 

 

27.5

22.1

15.0

11.6

9.6

7.9

6.7

 

 

 

 

 

 

5/16

.312

 

 

 

 

 

 

 

 

 

 

39.2

26.5

19.3

15.0

12.5

10.4

7.7

 

 

 

 

 

3/8

.375

 

 

 

 

 

 

 

 

 

 

 

42.7

31.2

23.8

19.5

16.3

12.4

9.6

 

 

 

 

7/16

.437

 

 

 

 

 

 

 

 

 

 

 

 

45.5

35.2

26.5

24.4

17.4

15.0

11.5

 

 

 

1/2

.500

 

 

 

 

 

 

 

 

 

 

 

 

 

48.5

39.5

33.2

24.6

19.5

16.1

13.4

 

 

5/8

.625

 

 

 

 

 

 

 

 

 

 

 

 

 

 

65.5

57.9

42.8

33.1

27.3

23.3

17.0

 

3/4

.750

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

92.3

68.1

53.0

43.2

36.2

26.9

21.0

7/8

.875

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

103.1

79.9

63.9

52.3

39.2

31.2

1

1.0

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

112.1

90.4

75.5

55.7

43.7

 

 

Shaded figures represent ideal conditions for light angle bending; punch with radius equal to metal thickness and die opening approximately 8 times the metal thickness. Resulting bend has inside radius approximately equal to metal thickness. If stock exceeds 1/2 inch in thickness, it is good practice to increase die's opening to at least 10 times the metal thickness. Bending pressures required for other metals as compared to 60,000 P.S.I. tensile mild steel on chart.

 

Soft Brass

50% of pressure listed

Soft Aluminum

50% of pressure listed

Aluminum Alloy (heat treated)

Same as steel

Stainless Steel

50% more than steel

Chrome Molybdenum

100% more than steel