The choirstalls of the basilica San Petronio in Bologna

The front of the basilica San Petronio in Bologna, Italy.

The Basilica of San Petronio is a large Gothic brick-built church dating from 1390. It is dedicated to Saint Petronius, who was bishop of Bologna in the fifth century and responsible for erecting the walls protecting the city. The construction of the church was a communal project of Bologna, not of the bishops. The church was planned to be larger than the Saint Peter's Basilica of Rome. These two things were likely the cause of the intervention by Pope Pius IV, and the plan was left unfinished. What makes the church interesting for medieval woodworkers are the choir stalls, created in the 15th century by Agostino de' Marchi, a woodworker from Siena. Agostino, famous for his intarsia work, had made a positive impression with his work for a private chapel in the Basilica, and was also commissioned for the choir.

The choir stalls of the San Petronio with a large lectern seen from the organ gallery.

The subjects of the intarsia for the choir are different than those found in other churches and chapels (e.g. the Chapel di Signori (1415) in the Palazzo Pubblico in Siena): there are no religious subjects depicted - except for one panel with San Petronio on it. Reason for this was that the basilica was a communal project, and not one of the diocese. In a previous post on medieval planes I mentioned that two of these panels showed woodworking tools, including several planes. I then only had  grainy black-and-white photos of these panels, where details were hard to discern. Reason to make a special appointment to visit the choir.

 The three panel with woodworking tools; the left and right panel have the same design.

Then there was a surprise: instead of two panels with woodworking tools, there were three, though one was a copy of the other. Also other panel images appeared more often, apparently the number of designs was limited. But there was another surprise as well. I thought that the workbench contained a holdfast, but this appeared to be not true. The place of my imaginary holdfast was a missing splinter of wood in the panel giving a false impression of something that is not there in the grainy black-and-white photo...

 No holdfast on this workbench; the panel has been popular with woodworms as well. 

Zooming in on the specific tools that are depicted: the double panel shows a chisel, a caliper and two planes. The plane on the left seems to have a double wedge, similar to the plane shown at a fresco 'the allegory of good government'  in the Palazzo Pubblico in Siena. The other panel shows a framesaw, six planes of different types, a toolchest and a workbench. Almost all planes have open handles at the front or back hand or at the sides, a common feature of Roman planes.

Left: the caliper next to the plane with the double wedge. Both the pin holding the wedge and the plane blade are clearly visible.  Right: the chisel and the top parts of the planes.

The framesaw hanging between two planes. The middle support is fixed with a pin, however the configuration shown here is not stable as the pin can slide of the frame. The saw blade is held by two wooden rivets, without handles to turn the saw blade.

 

The plane with two crossbars (left) and the rabbet plane on both sides of the crossbars.

The plane with side handles (left) and a round moulding plane (right) - the sole of this plane is rounded.

The other panels show different subjects: musical instruments, chairs, chests, books, lantern, vases, a chess game and another game board. Each image of the panel is surrounded by a plain 'mat' or 'passe-partout', and in turn by a frame with an intarsia pattern. There is even a 'secret' intarsia panel in the choir, masking a door behind. A selection of these panels is shown below.

 

Boxes and a vase with fruit.

 

Three legged chairs and a candle holder.

Two benches from different perspective.

Two 8 by 8 chess boards with a botch that supposedly holds the game pieces. Three of the chess pieces are shown on the right photo.

Other furniture

There is more medieval church furniture in the San Petronio. In the middle of the choir is a very large lectern for the music books showing the lines that had to be sung by the choir. As the choir members had to see the lines from a distance, the books and consequently the lectern had to be large. Some of these large musical books are kept in in the Museo Civico Medievale in Bologna. The lectern is also able to swivel, so both sides of the choir could see the content of the displayed book. The lectern can be opened to reveal a small cupboard.

The swivelling lectern (left) and a detail of the lectern showing a hinge of the cupboard (right).

To get an impression of the sheer size of the music books in the Museo Civico Medievale, curator Massimo Medica poses next to the book display. Photo left by Sunil Deepak;  right copyright Getty Images.

On the gallery above the choir are two organs, one of them from the 15th century (1476 by Lorenzo da Prato). The medieval organ originally used to stand at a different place in the church, where it would be visible from all sides. Not only the frontal woodwork of the organ is painted and gilded, also the backside is fully decorated and carved! Nowadays the organ has an encasing dating from later centuries. The organ still functions well, as can be heard here on YouTube.

(left) The organ pipes are decorated as well; around the pipes is a gilded gothic framework. Right: behind the organ, now invisible form the outside, the same gothic gilded openwork tracery and painted woodwork is found.

Our guides, when hearing I made medieval furniture, proudly showed the medieval chair for the cardinal (normally covered/protected by a piece of cloth). This was a highly carved Savoranola type folding chair, but more likely 16th century in nature than medieval.

The savoranola chair for the cardinal.

In the main area of the church, an unusual wooden pulpit can be found. It is not fixed to a pillar, which is commonly the case, but stands on its own legs. Though it is large object, it can be moved  to a different spot. Entrance to the pulpit is on the back side, where there is a door. (The stair has been removed for security reasons).

The wooden pulpit has a cloth baldachin.

Pieces of St. Thomas and St. Joseph

When visiting several churches and musea in Tuscany, Italy, we discovered some pieces of the patron saints of the woodworkers: Saint Thomas and Saint Joseph. The reliquary of St. Thomas likely contained another arm bone (his skeleton in Ortona is missing several arm bones), while that of St. Joseph contained an unknown piece of him. The containers for the reliquaries were 'modern', dating from the 17th and 18th century.

Reliquary of Saint Thomas (Tommaso), third quarter of the 17th century, gilded bronze.
 Santa Maria della Scala, Siena, Italy.

 

Reliquary of Saint Joseph (Giuseppe), 18th century. 

San Gimignano Museum of Sacred Art,  San Gimignano, Italy.

The medieval toolchest: the plane (part 6)

I thought that the medieval plane history was more or less complete in the five and a half previous posts. I was wrong, a book on archaeology in Schleswig-Holstein (Germany) did contain two medieval planes dating from the 11/12th century that were unlike any other medieval planes.

The wedgeless plane

The 1:3 photo from the archaeology book 'Ausgrabungen in Schleswig. Berichte und Studien 17'. The middle photo has a length of 63.6 mm in the book, meaning an actual plane length of 19.1 cm. Archeologisches Landesmuseum Schleswig, Inv. nr. KSD 389.014.

The plane from the Hafenstrasse 13 in Schleswig was found in 1982 during an excavation. It dates from the 12th century and made in out of one piece of Taxus. The front handle or toat is carved in the form of a male figurehead, while the complete plane has a more ship-like form. What is most unusual of this plane is that the plane blade is not secured by a wedge (against a pin or cheeks). Instead, the plane iron has a trapezoid form and secures itself in a groove that also becomes smaller at the top. So far no other plane is known that uses this method of securing the iron. The probable reason that this is the sole plane is obvious, this method is quite impractical.

Nevertheless, it was interesting for us to construct a replica of this plane and try it out. Although the article in the archaeology book also described a reconstruction of this plane, not everything was covered and we needed to find out much ourselves. We were lucky to have a large felled taxus tree available for our replica - thanks to castle Hernen.  From this a suitable block of wood was sawn, on which the plane was drawn. First, it was necessary to enlarge the image from the book (1:3) to its 100% size. This was a bit complicated as the three photos (top, bottom and side) did not have the same size and I had to adjust it with help of a photo program on the computer. Also, there were no front and back images available, nor a cross-cut drawing. The images were printed and cut-out with a scissor and used to transfer the plane drawing to the wood.

The Taxus block with the plane drawing.

First, the ship-from was drawn on the sides of the block. These were then cut out with a bandsaw. The top part was then glued back on with a piece of newspaper in between, so it could be easily broken of again. Then a drawing was made on the underside of the plane and also sawn by the bandsaw. Because the top part was glued back, it could function as a stable basis for sawing. After sawing, the top part was broken away.

Left: the top part glued back on with a newspaper in between. This way I could stable saw it when upside down. Right: the top part broken away again when the oval ship shape had been sawn.

Then the figurehead was carved with help of gouges and a carving knife. The hairs were filed. Finally, the figurehead was sanded and waxed. The remainder of the plane was not yet carved, as the space between the opening for the iron and the rim is rather small. My thought was that this was safer to do after the making the groove for the plane blade.

Some of the stages of carving the head. The plane was clamped in a vise, with a piece of wood to rest the head on. 

The author had measured the size of the plane iron with help of a paper mould. It was found that the iron had a thickness of 3 mm, a length of 65 mm, a width of the cutting edge of 42 mm and a top width of 25 mm. I did have a top part of a plane blade (the bottom part being used by another medieval plane) which was cut and sanded to the correct size. It appeared later that my choice of the blade was not very wisely made, as the top consisted of soft iron that was easily blunted by adding the iron to the plane and its following use.

My plane iron has a bottom width of 48 mm and a width of 46.6 mm at the point it leaves the plane. 

Top width is 26.6 mm. It has a total length of 63 mm. The blade was sharpened with a 30 degrees bevel.

I measured the angle for the iron using the top and bottom openings and found it to be 45 degrees - an angle comparable to that of modern planes. The description of the plane in the book mentioned an angle of 43 degrees. The hole for the blade was drilled out, but first a piece of wood was cut out with a chisel  so that the drill bit could do its work on a relatively horizontal surface. After drilling that the hole was cleared and enlarged by hand.

The power drill set-up, with the platform set at a 43 degree angle. A piece was cut out with a chisel to have a horizontal surface for the 6.5 mm drill bit.

The opening was cleared and widened with a chisel.

After that the groove for the plane iron needed to be made and fitted to the size of the iron. The basic groove was cut with a keyhole saw, which had a thick blade (slightly thinner than the plane iron) and could pass through the hole. Then the groove was carefully widened and enlarged, so it fitted the iron with help of a 2 mm mortise chisel and a 3 mm standard chisel. When the iron almost fitted, the remaining carving, sanding and waxing of the plane body was done. Then the iron was 'fixed' by placing the plane on a piece of soft wood and hitting it with a hammer at the top end.

The groove was sawn using a -bladed keyhole saw.

Carefully checking how the iron fits, each time the groove is widened a little bit.

The plane with and without the plane iron.

Also the top side and the underside of the tail are angled.

The plane has a comfortable grip and is easily pushed on a piece of hard or softwood. At the moment the blade is a bit dented (for reasons mentioned above) and set to produce very thin shavings. The latter is one of the drawbacks of this plane design: it can only be set at one specific depth. Perhaps you can adjust it by adding a thin strip of wood or paper into the groove; I have not tried this. Furthermore, if you need to sharpen the blade - thus making it 'shorter', you also need to plane a bit from the sole of this plane.

Side view of the plane. The basic body of the plane is only 28 mm high. The total length is just less than 20 cm.

The router plane

The 1:3 drawing from the archaeology book 'Ausgrabungen in Schleswig. Berichte und Studien 17'. The top drawing has a length of 53.1 mm in the book, meaning an actual length of 15.9 cm for this plane part. Archeologisches Landesmuseum Schleswig, Inv. Nr. KSD 382.011.

The second plane from Schleswig dates from the 11th/12th century and was excavated from the Plessenstrasse 83/3 in 1976. This plane was made from maple. Although only half the plane remains, its function was clear due to the iron nail holing a remnant of the wedge. The opening for the iron is large, and the wooden sides are relatively thick, which makes it likely that this plane functioned as a router plane. Also interesting is the decoration with a head of a duck at the end  of the plane. Also the reconstruction of this plane was described in the article by Karl-Heinz Gloy. We did not make this plane (yet). He estimated that the plane had a length of 23 cm, considering that the opening for the blade was in the middle of the plane. The opening for the blade was set at 3 cm; it has a width of 1.7 cm. The angle of the opening is 40 degrees. The length and width of the reconstructed blade were 75 and 15 mm, respectively, with a sharpening angle of 30 degrees. 

Sources

• H.E. Saggau, 2006. Gehauene und geschnitzte Holzfunde aus dem mittelalterlichen Schleswig. In: Holzfunde aus dem mittelalterlichen Schleswig. Ausgrabungen in Schleswig. Berichte und Studien 17. Wachholtz verlag, Neumünster, Germany, pp. 199-304.
• K.-H. Gloy, 2006. Ein Bohrer und zwei Hobel aus dem mittelealterlichen Schleswig. In: Holzfunde aus dem mittelalterlichen Schleswig. Ausgrabungen in Schleswig. Berichte und Studien 17. Wachholtz verlag, Neumünster, Germany, pp.305-310.