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close this bookMaking Permanent Joints - Course: Basic skills and knowledge of electrical engineering. Trainees' handbook of lessons (Institut fr Berufliche Entwicklung, 19 p.)
View the document(introduction...)
View the documentIntroduction
View the document1. Types and Meaning of Permanent Joints
View the document2. Tools for Making Permanent Electrical Joints (Bondings)
Open this folder and view contents3. Soldered Joints
View the document4. Wire-wrap Joints
View the document5. Notched Joints
View the document6. Pressed Joints

2. Tools for Making Permanent Electrical Joints (Bondings)

Tools for making permanent electrical joints are soldering irons, soldering baths, gasoline or gas blow torches, wrapping, notching and pressing tools. The use of such tools is to be adapted to the relevant application and local conditions.

Soldering irons

Figure 1 - Construction of an electric soldering iron - 1 bit, 2 fastening screw, 3 handle, 4 lead

Electrically heated by a current-carrying heating wire of a heating coil inside the metal housing of the soldering iron. The proper soldering iron is selected depending on the size of the soldering joint and on the necessary soldering temperature. Soldering irons with a capacity of from 6 to 400 W can be used.

Coordination of soldering iron - wire cross-section - solder diameter

wire cross-section (mm2)

up to


1.5 to 6.0

10 to 25

up to 50

capacity of soldering iron (W)

up to





solder diameter (mm)




all types

- For soldering work on printed circuit boards soldering irons of maximally 60 W are to be used.
- Soldering irons with a perfect bit are to be used for any soldering work.

Soldering baths

Electrically heated by a current-carrying heating wire of a heating coil in a stationary housing where the solder is molten.

Figure 2 - Schema of a soldering plating bath - 1 soldering tin vessel, 2 electric heating, 3 plug, 4 lead

There are two types of soldering baths:

- Dipping bath for soldering of wires
- Flow-soldering bath for soldering of printed circuit boards.

Gasoline blowtorch

Gasoline blowtorches can be operated independently of the electric mains and are mainly used for soldering large cross-sections.

The following instructions are to be followed when working with the gasoline blowtorch:

- Don't fill the gasoline tank with more than three quarters of its capacity.

- Close the gasoline tank tightly - make sure that the sealing in the screw cap is fitting well.

- Pour the spirit into the preheating bowl and ignite it. By preheating, the gasoline absorbed by the wick is heated and gasified in the gasifier.

- Before the spirit flame extinguishes, let gas from the nozzle into the blow pipe by opening the control knob and ignite the gas. The vent slots in the blow pipe will supply air so that the correct mix of gas and air will be generated.

- Adjust the flame correctly by means of the control knob.

- Use the first third of the flame for soldering.

Gas blowtorch

Gas blowtorches can be used independently of the electric mains and are universal in use by various nozzles and attachable bits. The following instructions are to be followed when working with the gas blowtorch:

- Make sure that all connections are tightly fitting.
- Don't interfere with the pressure relief valve.
- When working in cable shafts etc., place the gas cylinders outside the cable shafts.

Wrapping tools

Figure 3 - Wire wrapping tool (wrapping gun) - 1 wrapping mandrel

Figure 4 - Wrapping mandrels - 1 front bores

Wrapping tools are required to join one more solid copper conductors of 0.3 mm to 1.0 mm diameter by a tag or to separate them.

The wrapping mandrel is the front pan of the wrapping gun or wrapping needle, i. e. the actual wrapping tool. It is provided with two holes at its front end, one is exactly in the centre and one is off-centre. The centre hole accommodates the wrap pin to be joined with the wire. Because the wrapping mandrel must rotate around the wrap pin, this hole must be 0.1 to 0.2 mm larger than the wrap pin's diagonal. The off-centre hole accommodates the stripped wire. The corkscrew type wrapping needle serves for opening the joint.

Notching tools

Notching pliers are used to join a conductor with a cable eye or several conductors in a sleeve by notching or crimping. In order to be able to handle various conductor cross-sections, two adaptors are required for the notching pliers. The adaptors required for flexible copper conductors, for example, are

0.75... 1.5 mm2 and

2.5... 10 mm2 cross-section.

For smaller conductor cross-sections the crimping is done with a flat nose plier or adjusting plier.

Figure 5 - Notching pliers with tool insert - 1 direction of leading in the cable eye

Figure 6 - Tool insert - 1 movable grooved pin

Pressing tools

Pressing pliers are used to join a conductor with a cable eye by pressing. For handling various conductor cross-sections and various conductor materials, different pressing adaptors are required.

The adaptors required for flexible or multi-core conductors, for example, are:

- pressing head with cable shear cutter

- pressing head for copper conductors

0.75... 10 mm2

10... 120 mm2

- pressing head for aluminium conductors

16... 185 mm2

A hand pressing plier is required for pressed joints of 2.5 mm2 aluminium conductors and press-sleeve. The table below is to be completed with the respective tools.

material-closed joints

force-closed joints

form-closed joints