wooden handle attached to a steel tang. The wooden handle - in the pictures shown here are identical and it is only the shape of the tool that changes with the product. It doesn’t take much thought to realise that perhaps wood is not th e best material
make the blade of a non-ferrous metals such as Copper or Aluminium and so never have problems of rusting - a quick check of the properties of diff-erent metals might lead you to choose an alternative. Spend a few minutes now checking out what might be a suitable material to use. Open a Word ‘doc’ and make notes. When making different ‘steels’ altering the amount of alloying elements controls qualities such as the hardness, ductility, and tensile strength of the resulting steel. Steel with increased carbon content can be made harder and stronger than iron, but is also more brittle. The steel you have used in school has usually been mild steel but this wouldn’t really be suitable for garden tools as it rusts quite easily and is not particularly tough. Another point well worth considering in the design of garden tools - or many other metal structures - is that of making sure that ‘dissimilar metals are not used together in contact - or if they are special arrangements have been made to minimise the effects. (see the pictures showing a mop head secured with an aluminium rivet. This is not an error in this case but possibly an example of ‘built in obsolescence. Garden tool
manufacturers could use stainless steel - an obvious material to avoid rusting- originally invented as material to make gun barrels - a part of a rifle that really doesn’t want to corrode and become smaller through the steel rusting. It is also worth noting that manu-facturers use heat treatments to alter the qualities of steels - changing their toughness and hardness qualities. Tool steel is worth examining for its
qualities and composition. Now we have looked at metals for the blades it will be worth considering polymers and manufacturing methods for the handles.
09-05-2009 WR
Built in obsolescence