Saturday, 30 November 2013

Basic Equipments

The fretsaw is a general workshop machine. It is used to cut and shape light materials such as perspex, MDF and plywood. Fretsaws are made by different companies and they range in price depending on the quality of machine. The most expensive and probably the best are manufactured by the German company ‘Hegner’. These can be used to cut very detailed shapes and they are supplied with different types of blade according to the material that is to be cut.
Cheaper fretsaws are still very useful and they can cut a range of materials. The materials cut more easily if they are quite thin, for instance, any material thicker than 10mm would be difficult to shape. The general rule is that the thicker the material, the slower the machine operator pushes the work against the blade.

There are two types of machine drill, the bench drill and the pillar drill. The bench drill is used for drilling holes through materials including a range of woods, plastics and metals. It is normally bolted to a bench so that it cannot be pushed over and that larger pieces of material can be drilled safely.
The larger version of the machine drill is called the pillar drill. This has a long column which stands on the floor. This can do exactly the same work as the bench drill but because of its larger size it is capable of being used to drill larger pieces of materials and produce larger holes.
BENCH DRILL
PILLAR DRILL
SAFETY
1. Always use the guard.
2. Wear goggles when drilling materials.
3. Clamp the materials down or use a machine vice.
4. Never hold materials by hand while drilling.
5. Always allow the ‘chippings’ to clear the drill by drilling a small amount at a time.
6. Follow all teacher instructions carefully.

The bench drill is a smaller version of the pillar drill. This type of machine drill is used for drilling light weight pieces of material.
The example below shows the machine operator drilling a thin piece of perspex. The perspex is held safely in a hand vice which is held in the hand. NEVER hold work directly in the hand when drilling.
The on and off buttons are found on the left hand side of the machine and the handle controlling the movement of the drill on the right.
Most bench drills will also have a foot switch for turning off the drill.

Ratchet Brace                                               Hand Drill



G CRAMPS


  
G Cramp is an essential tool in the workshop and it comes in a range of sizes and is generally used for clamping work securely to a surface/workbench top. It can also be used to hold parts together whilst glue is drying.


Sash Clamp



Sash clamps are used to clamp work together when it is glued. They vary in size and are normally used in pairs. The lengths are normally from 460mm to 1370mm. The bar is made from cold drawn mild steel and the head and slides made from malleable iron.
After clamping a frame, the 'squareness' of the frame should be tested and adjustments made to the position of the clamps if necessary. The internal angles of the corners should be 90 degrees. The 90 degree angle is checked with a try square or a rule. A long ruler is used to check large frames and a try square is used on smaller ones. When using a ruler the diagonal distances are measured. If both measurements are the same, the angles at each corner are correct. If the two measurements differ, the clamps need adjusting until the measurements are the same.

EXAMPLES OF PLANES
  
WOOD BLOCK PLANE: Although this is a very old design they are still used today to remove a large amount of wood. This is due to the fact that they are lighter than steel planes and therefore they can be used comfortably for longer periods.
  
JACK PLANE: This is the steel equivalent of the wooden block plane. It has a steel body and because it is heavier than the wood block plane it is easier to hold down on the surface of the wood being planed. It is used to plane longer pieces of wood.
  
SMALL BLOCK PLANE: This is a small version of a wood block plane and it is used for light work such as producing 'chamfers'. It is normally held and used in one hand.
   
SMOOTHING PLANE: A shorter version of the steel jack plane. It is used for general work such as smoothing short pieces of wood. It is lighter and smaller than the jack plane
 
   
BULLNOSE PLANE: This is used to plain right into corners. The blade can be seen to go almost up to the end of the plane's body and consequently very little material is missed in a corner.
 
  
REBATE PLANE: Used for producing shoulders or rebates. A good example is a base to a jewellery box which is rebated into the sides. (See Lapped Joint)
  
COMBINATION PLANE: Used in a similar way to a rebate plane. It can be used for creating a shoulder/rebate on the edge of a piece of wood. This plane has an advantage over the rebate plane as it is adjustable for different widths. (See Lapped Joint)


  
MACHINE PLANE: This is favoured by DIY enthusiasts as it saves time. A blade revolves at high speed and as the machine plane is pushed across the surface of the wood - it is planed. A big disadvantage of these planes is that they are potentially very dangerous if misused. Also, sometimes the finish to the surface is not as smooth or precise as a hand held plane being carefully used.


Types of Hinges

A large variety of hinges are available from most hardware stores. The type bought depends on how it is to used and what it is to be fitted to. For example, when selecting a hinge for a jewellery box, a small brass butt hinge is likely to be used rather than a concealed hinge. Furthermore, brass hinges are more expensive than steel ones and they give a quality look to the completed product. Below are some of the more popular hinges that are available.
BUTT HINGE: Comes in a range of sizes from 13mm to 150mm and is normally used for cabinet doors. They are very strong but cannot be adjusted once they are fitted.
 
    
BUTTERFLY HINGE: This is often used on light-weight doors and different shapes and patterns are available. They are generally easy to fit.
    
 
    
FLUSH HINGE: This type of hinge does not require a recess to be cut. They are not as strong as butt hinges but can be used for light-weight doors and small box construction.
    
 
    
BARREL HINGE: This comes in two parts. The threaded part of the hinge is screwed into a pre-drilled hole. They are easy to fit and the hinge can be dismantled.
    
 
 

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CONCEALED HINGE: These normally come in two sizes (25mm and 36mm. The hinge is adjustable once fitted and is designed with chipboard and MDF in mind.
    
CONTINUOUS or PIANO HINGE
    
 
This is a hinge that comes in different lengths and can be bought in brass or steel. It is ideal where a long hinge is required such as a desk top or a cupboard door. Small countersink screws are normally used to fix it in position.

Types of Nails& Glues

ROUND WIRE NAIL - This is used for general work. It is not attractive in shape and it can split wood when hammered in position
OVAL WIRE NAIL - This is a long nail and care must be taken when it is hammered into the wood. It is unlikely to split the wood.
LOST HEAD NAIL - This is ideal if it is necessary to hide the head of the nail as a punch can be used to hammer the head beneath the surface level.
PANEL PIN - A very popular way of joining woods although glue is usually included as part of the join.
TACK - Can be used for fixing textile materials to wood for example, fixing upholstery to furniture.
SPRIG - This no head and is generally used for fixing glass to glass in wood frames.
ANNULAR NAIL - The teeth of this nail hold it in place firmly. Therefore, it is used for fixing plywood and other materials.
HARDBOARD PIN - The diamond shaped head is hidden when used in materials like hardboard
CORRUGATED FASTENER - This will hold the corners of wood frames firmly together


Woods can also be joined with the help of PVA glue. Modern glues are very strong and if adverts on TV are to be believed, joints made with glues can be stronger than the wood itself.

Cascamite is a waterproof glue and is probably the most effective glue of all. It is a white powder and is resin based and should be mixed in a glass or plastic container, two parts water to one part cascamite. It must be stirred thoroughly until it becomes a smooth/creamy paste. Cascamite is a quality glue and is suitable for all furniture especially if used outside as it resists rain water. The stages involved in the use of cascamite are outlined below.

1. Pour water into a glass container.
2. Pour powered cascamite into a glass container 
3. Stir thoroughly until a smooth creamy paste is produced.
4. Apply to both wooden surfaces using a spreader or a paint brush.
5. Push the two pieces together, rubbing the surfaces from side to side. This will ensure that air is not trapped and that the glue has been spread evenly.
6. Use cramps such as G Cramps to lock the two pieces together. Leave for twenty four hours before removing the cramps.


Glues For Plastics
Tensol Cement, Contact adhesive, epoxy resin, Super glue.



Friday, 29 November 2013

Other Types of Screws

RAISED HEAD SCREW: Used to fit door handle plates and decorative features that must look good.

(If the raised head was not there it would have been a countersunk slot head screw)



DOME HEAD SCREW: Can be used for fitting fixtures such as mirrors. The 'cap', which is the dome shape is usually chromed or made from brass and this can be a good feature. It also makes the head of the screw safe as the doom has no sharp edges to catch and cut hands/fingers.



Chip board ScrewThe thread on this type of screw extends all the way along the length. It is best used with chipboard

SELF-TAPPING SCREWS: these are normally used to cut a thread in metal. A hole is drilled in the metal, a fraction smaller than the width of the screw. The self-tapping screw is then turned into the hole cutting a thread.