The spring that returns the treadle to the raised position after each downward stroke can be made in several different ways.
Traditionally, it would have been a long pole, up to 20 ft (6m) in length. Often it would have been a tall sapling such as one finds growing among more mature close planted woodland. These tend to be long, spindly and will not survive under the canopy of the older trees. Ideally it should be about 2" (5cm) at the base and 1" (2.5cm) at the tip. In use the base is anchored to the ground or the base of a stout tree. An A frame of stout timber provides the fulcrum over which the pole is bent as the treadle cord pulls it down. A shorter pole will give a shorter, more snatchy action. Using such a pole is like riding a bike that it too small for you - painful and inefficient. The setting up and adjusting of the traditional pole requires some practice. Moving the fulcrum point along the pole will change its behaviour. Bodgers refer to this as 'tuning' since you are trying to make the natural frequency of the pole match with your natural frequency when pushing the treadle.
A simple alternative to the pole is to use a bungee cord or bicycle inner tube in place of a pole. It may not be elegant but it is a pretty good substitute. Points to note are that the distance between the supports of the bungee and the height of the bungee above the lathebed should be as great as is practical otherwise you will find in the first instance that the bungee reaches full stretch before the treadle hits the ground, and in the second instance the treadle cord pulls the bungee down to the work and the bungee then becomes a menace to the operator. Use an anorak toggle, the type with a spring in it to fix the treadle cord to the bungee so that you can release it easily. If you tie it on directly the knot will tighten onto the bungee making adjustment difficult.
A more complex alternative is the bow and bobbin. My experiments with this are covered elsewhere.
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