Oak wood is tough and durable. After a storm, the MOT was able to obtain two straight oak trunks from a forest in Antwerp. Pump borer Oscar De Wagter testified that his family used to go to the Ardennes to choose an oak tree that was as straight as possible without branches to have it transported to Nevele for drilling.
Elm wood used to be very commonly used by woodworkers such as the pumpmaker, but nowadays this tree species is difficult to find in Flanders. Fortunately, for this project we were able to use a few rare beams of good-quality elmwood to make the internal parts and some accessories on the lathe.
Apparently, wood from the larch tree was also used in our regions.
video: types of wood to make a water pump (Dutch spoken)
Letting draft horses do the work for heavy trunk hauling is part of our heritage. Using horses in forests instead of heavy tractors is a good way to prevent soil compaction. Horses need less space in between trees and can go deeper into the forest. They present a big ecological advantage.
The 'triqueballe' is a two-wheeled vehicle that was commonly used to move logs or heavy beams. It is a cart with two big wheels up to two meters in diameter attached to a heavy wheel block, to which one long drawbar is connected transversely. The drawbar remains upright due to a heavy counterweight. After the 'triqueballe' is driven over the trunk, it is fixed with a chain at the bottom of the wheel block. By pulling down the upright drawbar, it acts like a lever which lifts the trunk up from the ground. By carefully choosing the balance point of the trunk it is suspended slightly above ground level to be towed away by the draft horses. Smaller models of this cart can be towed by hand.
video: move logs and watering (Dutch spoken)
First of all, it is a form of stock management to keep the wood at the ready, both for sawmills and individual craftsmen. A suitable trunk could be obtained from this stock at any time. Watered oak logs for pumps were sometimes offered for sale in series. Pumpmakers often left several logs in a local ditch or pond for years, choosing the most suitable from their stock for each particular job.
The water stops the drying process so that the trunk does not start to split. Moreover, certain types of wood are much easier to drill when wet. This advantage is even more important for the pump borer who has to drill quite a lot of meters.
Another reason that is often quoted specific to pumps is that the water washes away all kinds of nutrients from the outer layers of the trunk, especially wood saps and tannins, which give off a blue color and an unpleasant taste. The wood saps attracts fungi and wood-boring insects, which can cause material loss, possible leakage and accelerated weather deterioration.
Elm especially has to water for a long time before processing. The internal pump parts made out of elm stay permanently wet when a pump is used up to 10 or 20 times per day. After installing the pump, it has to be used regularly not to run dry, risking the wood to burst. Oak wood can leach tannines, which make the water turn brown. Frequent use of an oak pump ensures pure water.