archaeometallurgy

A conical reamer for the tap maker

In Nuremberg the tap makers belonged to the redsmiths. This article is about a simple question of how the conical opening of a late medieval tap was dressed. Although you can do this completely manually, as I have shown in the short documentary, it is highly unlikely that it was actually done this way by the Nuremberg Red smiths or tap makers. Grinding the stop cocks into the tap takes several hours, even if the casts had a good fit to  begin with. Of course, it is not the spent labour time that has caused me to investigate the grinding of the stop cocks in more detail, it was rather the pictorial evidence that I found in Weigels book of trades and in the Nürnberger Hausbücher of the Zwölfbrüderstiftung.

Tap maker Hans Zeuller

Redsmith Hans Zeuller with conus reamer. Source: Wikimedia Commons

The tool with which Hans Zeuller uses is clearly visible inside of the tap We can assume that it is a kind of conical reamer; i. e. a tool used in a scraping rather than a cutting fashion. Metals are very dense and can hardly be cut by hand. Continue reading

Reconstruction: Early 15th century tap. The location is Zurich, Switzerland.

Some time ago I made a tap for a re-enactment brewer. I was already able to gain experience with the production of tap taps when I made my Aquamaniles. Therefore I decided to document the manufacturing process. Medieval taps often have a stylized cocks as a handle on the plug.  From the end of the Middle Ages taps or spigozs were made by the Zapfenmacher. One of the centres was Nuremberg. In the iamges of the Mendelsche and Landauersche Hausbücher of the Zwölfbrüderstiftungen it is interesting to note that the process step for the production of the taps shows only the reworking, but never the moulding. The illustration of the redsmith by Jost Amann in Hans Sachs book of trades gives at least a hint of the moulding material..

In the background, lumps of clay may have served as a raw material for the moulding material.

A little later again, in the 17th century, Christoph Weigel depicts the Zapfenmacher in its own right . Here a strong specialisation had taken place within a century.

The films are not about a strict archaeological experiment. Rather, it is a matter of examining some hypotheses on the manufacturing process. First and foremost, these were:

1. Is it possible to make a wax model where plug and tap fit snugly?
2. Can you cast this in such a way that there is little rework?
3. How can the grinding of the plug into the tap be mastered manually?

Have fun watching. As always, I am looking forward to your criticism, questions or suggestions.

The first part deals with the history of the tap and the production of the wax model.

The second part is about moulding the wax model, pouring the tap and the first cleaning after casting.

The third part is about finishing the cast tap. This means that it must be roughed, filed, drilled and ground. The grinding of the plug into the tap’s body was particularly exciting. In fact, absolutely leak-proof tap can be produced with the simplest of means.

References

Aristotle and Phyllis aquamanile, 2015 by Bastian Asmus made after a 15th century original from the low countries.

Aristotle and Phyllis in the  Malterer tapestry. Now in the Augustinermuseum Freiburg. Source: Wikimedia Commons.

The Middle High German lay of Aristotle and Phyllis probably originated in the 13th century in the upper Rhine region between Basel and Strasbourg. The story was a popular motif and is found not only in sculptural works, but also in tapestries and drawings. King Philip of Macedonia’s  son Alexander, later called the Great, is educated by Aristotle. The young Alexander, madly in love with the beautiful Phyllis, is scolded by his teacher for his mental absence and warned of the dangers of love and/or women. Aristotle effects the separation of the lovers through intervention with the King. Musing on revenge beautiful Phyllis seduced Aristotle.  As price for her love she demanded that she could ride around in the gardens on his back. Whilst doing so Aristotle is discovered by the Queen and Aristotle falls prey to shame and disgrace, because he could not meet his own requirements. He was exiled and pondered over the wickedness of the world.

Aristotle and Phyllis. Hausbuchmeister 15th century. Source: Wikimedia Commons.

The Aristotle and Phyllis aquamanile was modelled in wax and cast in  the lost wax technique. It can now be seen in the newly founded European Hanseatic league Museum.