Eidsborger grindstone quarry

In the Eidsborger sharpening stone quarry (Norwegian: Brynesteinsbrot ) stones were mined that were coveted as sharpening stones for blades of all kinds for centuries.

location

Eidsborg is a small district of Tokke municipality in the Norwegian province of Vestfold og Telemark . It is located about three kilometers north of the main settlement Tokke at an altitude of 530 meters. The place is also known for its stave church .

The quarry can be seen from the Vest Telemark open-air museum with the stave church on the slopes of the mountains. It is located a few hundred meters north of road no.45, which runs from Dalen to Høydalsmo , and can be reached via an inconspicuous beaten path after crossing a stream .

history

The operation and export of the grindstones is documented until the 8th century, but probably even longer. From around 1000 the Eidsborg grindstones dominated the area around the entire North Sea. Ports of export were Skien and Langesund . Merchant ships used the grindstones as tradable ballast.

Initially, the stone was a resource that farmers mined when needed, as it could also be used to pay tax debts. In 1358 it was decided that only citizens of the town of Skien had the right to trade the stone. The quarry was temporarily privately owned and temporarily owned by the church. In 1778, local farmers acquired trading rights and set prices and quotas at an annual “Steinthing”. There was a great boom after 1800.

Although the deposit was not exhausted, operations were closed in 1952 for economic reasons. The stones are no longer available in stores.

Mining methods and processing

The stones were broken into long, narrow units with wedges, which were mainly used as whetstones for scythes , by means of fire, the exploitation of frost blasts and later with industrial explosives . In addition, small stones were created for the “trouser pocket” and larger “bench stones” for the workshop and kitchen. The usable areas were ground flat with simple machines.

The material

The stones consist of a very fine, thin-layered and even quartz - mica slate of gray color, which sometimes shows traces of iron oxides . Fine-grain and coarse-grain stones are known.

Todays situation

Apart from the large garbage dumps on the slope of the mountain, there is not much left of the former production. However, it is possible to find chunks of stone on the heaps that are ideally suited as whetstones after they have been prepared (flat grinding of the usable area). The surface grinding is done relatively quickly with silicon carbide as a rolling grain with the addition of water on a ceramic plate.

Grinding stone obtained from the quarry dump and ground flat with Ajikiri knife and size comparison

Garbage dump of the quarry on the road no. 45 at Eidsborg

Grinding properties of the Eidsborg whetstones

The stones are to be classified as rather hard and have a grain size that, according to the JIS scale, is around 1500 to 2000. The grinding pattern on a blade is finely scratched and can go as far as polishing. The cutting edge reaches an aggressive sharpness that is very suitable for processing food. The stones are less suitable for very blunt blades. The area of application is in the area of sharpening and honing blades with an already existing basic sharpness.

The stones are to be used with water, moistening is sufficient, long soaking is not necessary. Dry grinding can clog the stones. Occasional rubbing with the same material or dressing is recommended.

Trivia

In the Vest Telemark Museum in Eidsborg there is a detailed account of the grinding and processing of the grindstone. Equipment and tools are shown and the facts listed here are presented.

source

Writings from the Vest-Telemark Museum Eidsborg / Telemark