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Wood Turning (PowerPoint)

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					Wood Processes
  PRODUCT DESIGN
Wood Turning
      The Lathe
Wood Turning
      This machine is a piece of equipment which is used to turn timber into round shapes, like
       round table legs, lamp bases and wooden bowls.
      The timber blank is held in the machine and a cutting tool is brought into contact with the
       revolving wooden blank which gradually takes on a cylindrical shape as wood is cut away.
      The woodturning lathe is a relatively simple machine consisting of two stands, a bed, a
       headstock, a tailstock, toolrests and electric motor providing the drive through a system of
       pulleys and a belt.
                                         headstock
      faceplate
                                                                                          tailstock




                                                                                     toolrest

      electric motor
                                                                                   bed
The Lathe
   Wood turning is the process of forming round objects on a lathe.
   There are two methods of turning, between centres and faceplate
    turning.
   Turning between centres is used to produce long cylindrical items such
    as table legs.

                  between centres




                                                     faceplate turning



   Turning with a faceplate is used to produce items such as bases or
    bowls. As the wood rotates, special cutting tools are used to create
    shape.
The Power Router
       Product Design
Routing
   Routers are typically used to cut grooves, hollow out larger areas and
    create decorative trims along the edge of a piece of wood. The shapes
    that can be cut by your router are limited only by the number of router
    bits that you own.
Routing
   Router bits can be categorised in two camps: edge bits and non edge
    bits. Edge router bits have small nylon (or metal) wheels on the bottom
    of them (see picture) that run along the wood. This allows you to rout
    along the edge of the wood without using a fence. Non-edge bits do not
    have this wheel, and are therefore more commonly used when routing
    a groove down the middle of a piece of wood. However, they can also
    be used along the edge of the wood as long as you use a rip fence or a
    router table.
Routing
         Router bits are made out of either High
     Speed Steel (HSS) or are Carbide Tipped.
     Carbide Tipped are far better, although they are
     significantly more expensive. However, as
     Carbide Tipped bits last up to 20 times longer,
     they do work out to be cheaper in the longer term.
    To rout a straight groove, either use a rip fence, a router table or
     clamp a straight rule across the wood so that the router can guided
     along it. It is important to note that there is a right and wrong way to
     run your router along the edge of a piece of wood. Typically routers
     rotate in a clockwise direction (when viewing the router from the top).
     It is therefore best to move the router from the left towards the right
     (when facing the wood). Routing in the wrong direction will cause the
     router bit to dig into the wood and may cause splintering of the wood.
     To ensure that your router abides by the left to right rule, consult your
     router manual.
Spindle Moulding
       Product Design
Spindle Moulding
     Spindle moulders are mostly used for cutting mouldings and certain
      woodwork joints. The machine consists of a cutter block that rotates at
      high speed on a vertical spindle protruding through a hole in the
      worktable. Adjustable fences guide the work past the cutter block. A
      large variety of shaped cutting tools are available for spindle moulders.
      All wood working machines need to be handled with care, but a spindle
      moulder can be particularly dangerous.

                              Fence

           Work
           piece                                     Tool




       Table
Spindle Moulding
   Special purpose spindle moulding machines are made for industry.
    The range of mouldings is vast and most timber merchants carry large
    stocks.
           Spindle Moulding Machine

                                                          MDF




   Examples of mouldings include door and window frame section.
    Virtually any timber can be used for mouldings, but those with finer
    textures give smoother surfaces for final finishing. The properties of
    MDF make it especially suitable for mouldings that are usually finished
    by coating.
Spindle Moulding
Spindle moulding machines are used to cut decorative edges and panels in a
range of furniture.
   Joining
Product Design
Jointing – Frame Construction
      Mortise and
      Tenon Joint            Cross Halving Joint




                              Bridle Joint

       Tee Halving




      Dovetail Tee
      Halving Joint


                      Chair Frame        Picture Frame
Jointing – Box and Carcass
Construction


     Rebate Joint          Through Housing Joint




                             Finger Joint
      Stopped Housing
      Joint
                                               Drawer Construction




          Dovetail Joint
Laminating
 Product Design
Laminating
Definition: A board consisting of layers
of wood bonded together with the grain
from each layer at right angles from the
neighbouring grain.
Machines
Product Design
Mortising Machine
   Heavy duty mortising machines are found in industrial
   workshops where cutting mortise and tenon joints is
   an integral part of the mass production process.

   Hollow Chisel Mortiser
   This machine has a special auger drill in the centre of a square, hollow
    chisel that has four cutting edges. When plunged into the workpiece it
    cuts a square hole. The drill cuts out the waste whilst the chisel
    squares off the corners. To cut a long, rectangular mortise the
    workpiece is slid sideways between each cutting.
Bandsaws
The bandsaw is an efficient, versatile
machine whose main uses are handling
large quantities of wood and shape cutting.
It can cut thicker timber than the average
circular saw and the thin blade means that
wastage is minimal. The blade itself is a
continuous loop of metal driven over two
or three large wheels. A bandsaw can be
used to cut outside curves but not inner
curves without cutting through the material.
Jigsaws
   The jigsaw is a very versatile tool. It will cut any man made
    board and rip or cross cut solid timber reasonably well. Its real
    advantage, however, is its ability to make curved cuts. When
    fitted with appropriate blade the jigsaw will also cut sheet metal
    and plastics
Fretsaws
   Powered Fret saws are usually connected with lightweight craftwork and
    model making. A fret saw can be used to produce very accurate work as
    well as being able to cut very tight curves.
Finishing
Product Design
Finishing
       Stains/ Dyes - To change the colour of wood and retain the texture and
        grain a number of dyes and stains are available.
       The stain/dye can be brushed on to the wood or applied with a tightly tied
        rag .
        Allow to dry and coat with varnish or wax to seal the surface.

       Oil/Wax - Some timbers, e.g. teak do not varnish well because their own
        oil content and should be finished by applying a teak oil or similar
        product. They can also be waxed to seal the surface.
       The oil or wax should be applied in thin layers with rag and polished
        thoroughly with a clean rag between coats.
       The more work put in, the better the finish!

       Preservatives – For timber used externally. Creosote is the cheapest
        and most common and once applied the brush should be cleaned
        thoroughly in paraffin before washing with soapy water leaving it to dry.
        Wood preservatives are normally harmful to the skin. Safety goggles
        and gloves should be worn and contact with the skin avoided.
Finishing
   Painting Wood - There are a number of advantages in applying paint
    to wood
   it protects the surface
   b) it means less expensive timber can be used
    c) the colour can be changed to match any new colour scheme.


    STAGE 1 - once surface is prepared a primer coat should be applied
    and allowed to dry. It will seal and protect the surface. When dry
    lightly rub with glass paper.
   STAGE 2 - the undercoat should be applied. The shade should
    match that of the finished coat.
   STAGE 3 - the final coat should be applied. There are a number of
    types available, gloss, eggshell, matt vinyl, etc.
        After each coat is applied, the brush should be cleaned
    thoroughly in turpentine and then in warm soapy water before being
    dried ready for use in applying the next coat.
Finishing
   Varnishing - will protect the surface of the wood and will allow the
    natural colour and texture of the wood to be seen.
   STAGE 1 - the first coat of varnish will seal the surface of the wood.
    For this coat the varnish should be thinned with turpentine in equal
    amounts and applied in a thin, even coat to all surfaces. When dried,
    the surface should be rubbed down carefully with steel wool.
    STAGE 2 - Further coats of varnish should be applied until the required
    finish is achieved. Steel wool should be used between each coat to
    smooth the surface.

				
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posted:11/30/2011
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