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If on the working drawing no details on the rivet are indicated, the following has to be taken into consideration:
The diameter of the rivet shank shall be at least one quarter of the thickness of all plates to be riveted - formula:
D = diameter of the rivet shank
s = thickness of all plates to be riveted (clamping length)
Figure 22 - Riveted joint:
1 - Diameter of the rivet shank
2 - Length of the rivet shank
3 - Allowance
4 - Clamping length
The length of the rivet shank has to be calculated on the basis of the thickness of all plates to be riveted:
The rivet shank must be longer than the thickness of all plates to be riveted by the measure of the "allowance" - formula:
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L = S + z |
L = length of the rivet shank
S = thickness of all plates to be riveted
Z = allowance
The allowance depends on the kind of rivet and on the field of application:
- Button closing heads in steel construction;
For rivets of diameters of the rivet shank up to 20 mm -
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Z = 1.5 x D |
For rivets of diameters of the rivet shank of more than 20 mm -
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Z = 1.6 x D |
- Button closing heads in boiler construction:
For rivets of rivet shank diameters up to 20 mm -
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Z = 1.7 x D |
For rivets of rivet shank diameters of more than 20 mm -
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Z = 1.8 x D |
- Countersunk closing heads in general:
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Z = 0.5 x D |
Rivets which are too long must be cut - the right length of the rivet shank is the precondition of the quality of the closing head.
Calculating example:
A button head rivet shall be calculated in order to connect two plates of 4 mm in thickness in steel construction:
1. Diameter of the rivet shank:
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D = 2 mm |
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selected: 3 mm |
2. Length of the rivet shank:
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L = S + Z | |
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Z = 1.5 x D = 1.5 x 3 mm |
Z = 4.5 mm |
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L = 8 mm + 4.5 mm |
L = 12.5 mm |
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selected: 12 mm |
Result: A rivet with the designation button head rivet 3 x 12 can be used for the intended connection.
Exercise:
A countersunk riveting of three 5 mm thick plates shall be made
What rivet can be used for this
purpose?
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