After drilling the trunk, the pump borer has to finish the pump mechanism. This involves both turning and forging the pump fixtures. The proof of the pudding is the mounting of the pump crank.
Once the drilling is done, the pump body that remains visible above ground has to be squared and smoothed with saws, chisels and planes. This can be done roughly or more refined depending on the location and purpose of the pump. It is essential that the crank is mounted in such a way that the user can pump ergonomically and the pump bucket can move up and down in the pump body. To support the hinging of the crank, the top of the trunk is usually sawn into two characteristic protrusions. An alternative way is to attach a separate piece of wood to the side of the trunk to attach the crank to.
A spout hole is bored with the auger about 15 to 30 cm from the top, into which the conical wooden pump spout will be driven to allow the water to flow out. To draw the water in, a side inlet is drilled 25-50 cm from the underside of the trunk, so as not to suck sludge, sand or other sediment from the bottom of the well.
Sometimes a worn-out pump was pulled out of the well and turned over to serve for a few more years. The bottomside then had to be reworked to make a support for the pump crank. The spout hole then became the bottom inlet and vice versa.
video: finishing the pump
The wooden parts in the pump body are mainly conical in shape. Usually the pump driller turnes them on a lathe himself. Our woodworker Luc Verachtert turned the elmwood parts with scrapers, while a woodturner would turn the elmwood parts with chisels. This is the only step in the project where we used electrical woodworking machines such as a lathe, circular saw and column drill.
- Since the water is not drawn in directly at the bottom, but through a side cavity, the original borehole must be closed by tightly tapping a simple conical tap. During the turning, a few grooves are provided to wrap the tap with flax or hemp. This is rubbed with grease, often sheep's candle wax, to make it waterproof.
- The pump lock is a cone-shaped, pierced piece of elm wood, provided with a leather cover, weighted with a wooden block. This piece of leather is beaten on one side so that it serves as a non-return valve. The pump lock is fixed at the level of the conical transition from the trunk to the pump body and is also made watertight.
- The pump piston is irregular in shape and thus requires some cutting and drilling. It has a round leather collar for a good fit, no water to leak and yet not too stiff. These leather parts were made on the basis of a mold. The pump driller had a series of molds in his workshop for various sizes of pumps. The piston is attached to a long rod, the pump rod, which is screwed to the crank that moves it up and down in the pump body. Originally even this pump puller was made of wood, but we opted to forge a metal rod.
- The type of pump we manufactured has a transverse hand crank. Its shape could vary by region. We attached a piece of elm wood, nicely cut to shape. Some pump borers kept the central taproot on the tree when felling because it was ideally suited for working into a servant. Bear pumps also work with a swinging servant because they rise higher above the ground and to apply more power. Namely, the pump body had a larger diameter and could be heavier.
- The pump spout is a long and conical piece of elm wood that is hammered horizontally into the spout hole to allow the water to flow smoothly and cleanly into a container.
video: making the pump parts
Oorspronkelijk werden waterpompen geheel in hout vervaardigd. Naarmate de kostprijs van metalen daalde, werd er geleidelijk meer ijzerbeslag toegevoegd om het mechanisme van de zwengel en onderdelen van het pomplichaam sterker te maken. Het smeedwerk in ons experiment is beperkt tot de stang aan de pompzuiger en het beslag aan de pomptuit. Door een ijzeren versteviging tussen tuit en stam kan de tuit een emmer dragen tijdens het vullen zonder door te buigen. Het smeedwerk werd verricht in de smidse van het MOT aan het Guldendal door Luc Verachtert met behulp van vrijwilliger Patrick Tas.