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For example, being able to mount an irregularly shaped piece of wood between centres is useful for establishing
the centres of balance. Again, even where the main turning will be carried out with the work mounted in a chuck or faceplate, strain on the primary fixing is more or less eliminated when rough shaping is carried
out with the tailcentre brought up to give support. Lastly, in the very final stages of production, being able to hold a vessel purely between centres (with the addition of bungs, soft pads etc.) facilitates the removal
of any evidence as to how the work was held.
A
four prong centre
is generally best for driving as it does not exert the wedging and splitting force of a two prong centre under compression. (With all centres, once their positions in the ends of the work have been decided on, it is a good idea to "pop" them using a wooden or leather mallet. This enables them to have good purchase without using *excessive pressure, which in itself can force the wood to bow and flex even before the cutting tool is applied.)
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