joining methods

Question 1

what are the 2 types of joining methods

Answer 1

permanent and semi-permanent

Question 2

difference between permanent and semi-permanent joining methods

Answer 2

permanent joining method can’t be undone without damaging the material but semi-permanent can be undone without damaging the material

Question 3

what are the 4 joining methods for wood that we need for GCSE

Answer 3

butt joints
mitre joints
dowel joints
housing joint

Question 4

what adhesive do we use to join wood

Answer 4

PVA glue

Question 5

what are the 4 joining methods for metals

Answer 5

soldering
brazing
welding
rivets

Question 6

what is a butt joint

Answer 6

joined end on
the glue is the only hold
weakest joint

Question 7

what is a dowel joint

Answer 7

wooden rod added to joint
use pillar drill to make matching holes
add dowel and glue joint
dowels would stop the pieces from sliding off one another and twisting
increasing tortional strength

Question 8

what is a mitre joint

Answer 8

cut at 45 degrees angle
that increases the surface area you are gluing stronger joint than butt
only for corners

Question 9

what is a housing joint

Answer 9

rebate/groove cut into one piece that the other piece rests into
mainly use in shelving
mechanical hold in shelving
mechanical hold as well as the glue so it can support more weight
has to be in the middle, not used on corner

Question 10

what is a wood screws

Answer 10

these give a strong fixing between wood as the threads pull the pieces of wood against each other. pilot and clearance holes are often needed.

Question 11

what is a countersunk screw

Answer 11

flat head

Question 12

what is a round head screw

Answer 12

round head above surface

Question 13

what is a nail

Answer 13

nails are the quickest way to join pieces of wood. they can be used without glue and are hammered into wood. nails are quicker to use than screws but the joins in not as strong.

Question 14

what are the 3 different types of nails

Answer 14

panel nail
oval nail
wine nail

Question 15

what are bolts

Answer 15

they are square or hexagonal head and are tightened with a spanner. they are usually made from brass, steel or stainless steel, and are self finished or plated

Question 16

what is a washer

Answer 16

are usually under the nut o spread pressure and protest materials

Question 17

steps for placing in a flat head screw

Answer 17

1 drill the pilot hole
2 use countersink to create a slope
3 tighten with drill or screwdriver

Question 18

what is a permanent joining method

Answer 18

permanent: a joint which cannot be reversed without causing damage to the material (the joint is intended to stay put for the life cycle of the product).

Question 19

what is a non-permanent joining methods

Answer 19

semi-permanent: a joint which can be reversed without causing damage to the material (the joint can be disassembled perhaps for repair, maintenance or transportation purposes).

Question 20

what are the different between soldering brazing and welding

Answer 20

Soft soldering, brazing and welding are permanent methods of joining metal parts using intense heat. In simple terms, soldering and brazing cannot melt the metal parts together but the joint can be heated and filled with a ‘filler metal’ ensuring a strong and permanent bond.

Welding is a much higher temperature method of joining metals than soldering and brazing which actually melts (fuses) the metal parts together. Welded joints are also permanent and the strongest way of joining metals

Question 21

what is soft soldering

Answer 21

Soft Soldering

Soft soldering is the process of permanently joining metal parts which are generally small or which may become damaged using very high temperature joining methods. Soft soldering uses a filler metal (solder) which melts at temperatures below 450°C, this is commonly done in two ways:

1. Using a soldering iron (to join electronic components).
2. Using a gas or electric torch (to join metals objects e.g. jewellery, copper pipes etc.).

Applying high levels of heat to metal will cause a vapour oxide to form on the surface and prevent the solder from adhering to it. A type of paste known as flux should be applied to the joint beforehand to prevent oxidisation and help ensure that the solder adheres to the metal.

Question 22

how do you soldering electrical components

Answer 22

Soldering electronic components

Soldering is widely used for joining electronics components and wires as shown in Figure 1. A soldering iron is required rather than a naked flame from a gas torch as this would obviously burn the components and the Printed Circuit Board (PCB). Flux is not normally necessary as most manufacturers produce solder with flux contained inside. Components which could be easily damaged by heat should be protected with a heat sink, for example, by attaching a crocodile clip or using long nosed pliers to draw the heat away from the component (but not the joint).

Question 23

what are the 5 step process for soldering an electrical component

Answer 23

Soldering process:

1. Ensure copper tracks/pads on the PCB are free from grease and fingerprints.
2. Insert electronic components / wires into the PCB.
3. Heat the joint evenly with the tip of the soldering iron.
4. Apply solder to the joint.
5. Remove soldering iron and solder and allow the joint to cool.

Question 24

how do you solder metal objects

Answer 24

Soldering metal objects

Soft soldering is an excellent joining method for joining metal objects which are not subject to mechanical stress. It is widely used by jewellery makers and plumbers. The bond is achieved by using a gas torch to melt the filler metal (solder) which flows into the joint as shown in Figure 2. Using flux is vital.

Question 25

what is the step by step process for soldering metal objects

Answer 25

1. Clean the joint ensuring it is free from grease and fingerprints (use wire wool if necessary). 2. Secure metal parts closely together with minimal gaps. 3. Apply flux to the joint (to prevent oxidisation). 4. Heat the joint evenly and apply solder. 5. Allow to cool.

Question 26

what is brazing

Answer 26

Brazing uses a filler metal which melts at temperatures above 450°C. It is a similar process to soft soldering but is much stronger because a brass alloy is used as the filler as shown in Figure 3. Although brazing it is not as strong as welding, it is much more precise and dissimilar metals can be joined.

Question 27

what is welding

Answer 27

Welding uses extremely high heat to join metal by fusing (melting) the parts together. Welding is the strongest joining method and is usually associated with gas and high current electric (arc welding). however, laser, friction or ultrasonic energy can also be used to join plastics and other dissimilar materials. The following industrial methods are widely used for joining metal and can be used in school workshops.

Question 28

what is oxy-acetylene

Answer 28

This type of welding makes use of acetylene gas and oxygen to create a flame of around 3000°C which melts metal parts together (a filler metal can be added). Oxy-acetylene is used less frequently than arc welding (see MIG and TIG below) but does have the advantage of being portable since an electric power source is not required as illustrated in Figure 4.

Question 29

what is MIG and TIG welding

Answer 29

MIG and TIG welding make use of an electric arc and gas to join metal as illustrated in Figure 5. MIG (Metal Inert Gas) and TIG (Tungsten Inert Gas) fuse metal parts together at temperatures of up to 20000°C. In TIG welding a filler metal (rod) can be used as an option but in MIG welding it is fed into the joint semi-automatically (through a spool). MIG and TIG welding are by far the strongest joining methods for joining metal and can even be fully automated using robot technology.

Question 30

what is knock-down fitting

Answer 30

Knock-down fittings are a type of mechanical joining method used to assemble products such as flat pack furniture, kitchen units, beds etc. There are many different types of knock-down fitting but they generally use some type of screw fixing, dowel, bracket or block to pull the joint together.

Question 31

what are the 4 Typical Knock-down fittings

Answer 31

Typical Knock-down fittings include: cabinet screws cam lock fittings cross dowels shelf supports

Question 32

Advantages of Knock-down fittings

Answer 32

Knock-down fittings can be used by anyone who has access to screw-drivers or Allen keys. There is no need for the 'assembler' to mark out, cut or drill. A cam lock fitting cleverly pulls the man made panels together giving a precise finish. The cam lock is hidden so as not to impact on the aesthetic look of the product. Knock down fittings provide companies with the option for flat-pack assembly which makes large products easy to store and transport thereby saving money. Knock-down fittings can also be cost effective as a joining method as they do not require expensive equipment or skilled labour. Another perceived advantage of knock down fittings is that the product can disassembled again if required.

Question 33

what is threading

Answer 33

Threading in metal involves cutting precise helical grooves to create screw-like structures or connections.

Question 34

what is tapering

Answer 34

Tapering in metal refers to gradually reducing the diameter or thickness of a metal component towards one end, often to facilitate fitting or assembly.