Drawing for flat arch showing relieving arch above and secret key joint
The flat arch on the north elevation (roof side) of the southwest tower is in three pieces. It spans an opening of eight feet. The visible joints of the keystone are perpendicular thus giving a gravity defying impression, but in fact concealing arch joints. A brick relieving arch was built in the hearting above to discharge some of the load above away from the opening.
secret key joint for flat arch
Details from Practical Masonry, by William R. Purchase
“I remember us having quite a lot of difficulty with the installation as the pieces were quite large and unwieldly and difficult to position on the falsework. I think Jim Bambridge had long awaited a chance to use this type of arch.”
– Steve Boyle, Master Mason
The title block for the unique flat arch for the tower drawing above, rendered March 29, 1980, by J. R. Bambridge, Master Builder.
Stephen Boyle was raised in Yorkshire, England. He began working with stone at age 18 at the Yorkminster Cathedral stoneyard. After his three year apprenticeship he started on restoration work at Salisbury Cathedral. Both cathedrals dated from the 12th century. Salibury Cathedral is pure Gothic throughout. James Bambridge hired him to begin the setting of stone on the Southwest Tower in 1981.
Special thanks to Steve Boyle for all the information and images in this post.
The Building Committee of the Cathedral announced its intention not only to complete the choir structure, but also to continue to the westward and construct the Crossing. The providing of necessary funds would accomplish the three new arches and cover for the crossing.
The pillars being in place, the next step will be the erection of three more arches. They will be precisely the same as the great eastern arch already erected. These four arches complete the square of the crossing. The Belmont Chapel is about complete and the Chapel of St. Columba has started. The Committee needs an additional $500,000 beyond funds on hand and other commitments. Regarding the Crossing area, The Building Committee of the Board of Trustees said the following:
“It is estimated that $200,000 would complete the choir. If finished it would easily accommodate a comparatively small number of worshippers. It is in the judgement of the committee, highly desirable that, in addition to the great stone arch now standing, there should be three similar ones needed to enclose the ‘crossing.’ Were the ground thus bounded to be temporarily roofed over and walled in, we should have an interior capable of accommodating from four to five thousand worshippers.”
– The Building Committee
Completing the Arches
All of the piers and columns for the next three arches came up from bedrock in an orderly way. Granite blocks for these structures kept arriving at the site. The western arch was the first to complete.
Western Arch Progress
Keystone For Western Arch, August 10, 1908
The North Arch was the next to complete
North Arch Complete. October 1908South Arch Voussoirs. Lower Ring Complete. November 1908
Setting the South Arch Keystone. November 24, 1908
Voussoirs on the arches and buttresses
Keep in mind, when Heins & La Farge designed the arches, they were to support a massive lantern and tower. The lantern would fill the crossing with light from large windows. With that in mind, the arches would need to be quite massive. Arch construction depends essentially on a wedge. If a series of wedge-shaped blocks, ones in which the upper edge is wider than the lower edge, are set flank to flank, the result is an arch. Voussoir is the term for these blocks on both the arches and the buttresses.
Voussoirs on North Arch 1908Voussoirs on Buttress
Notice the staggered joints on the voussoirs that are side by side. A row of two voussoirs is flanked on each side by three voussoirs. This design further strengthens the arch.
Additionally there are three sets of these voussoirs front to back to further create these massive arches. Numbering the stone determines its exact location. Each voussoir must be precisely cut so that it presses firmly against the surface of neighboring blocks and conducts loads uniformly. The pressure downward on an arch has the effect of forcing the voussoirs together instead of apart. These stresses also tend to squeeze the blocks outward radially. Loads divert these outward forces downward to exert a diagonal force called thrust. These forces will cause the arch to collapse if it is not properly buttressed. Therefore the vertical supports upon which an arch rests must be massive enough to buttress the thrust and conduct it into the foundation.
Voussoir
The word is a stonemasonry term borrowed in Middle English from French verbs connoting a “turn”. Each wedge-shaped voussoir turns aside the thrust on to the supports. Voussoir arches distribute weight efficiently, and take maximum advantage of the compressive strength of stone.
Photo Credits – All photos from the Irma and Paul Milstein Division of the United States History, Local History and Genealogy, The New York Public Library. Manhattan: Amsterdam Avenue – Cathedral Parkway
March 20, 1986. Group around gablet. – Photo Robert F. Rodroguez
The group above all participated in the creation of this beautiful gablet destined for the east face of the southwest tower. They are Nick Fairplay – top, to the right Joseph Kincannon, Jose Tapia, D’Ellis Kincannon. Bottom row R-L Frank Walcott, Ruben Gibson, Angel Escobar, James Jamerson, Alan Bird, and Al Rivera. Left side top Eddie Pizarro, then Cynthia Linton. Some were on the saws and planers, some were cutters and some were carvers. Frank Walcott was the business manager.
This gablet or gable for the tower consists of some 25 different stones, cut and carved in the stoneyard. It is built into a wall of the tower as shown here as opposed to the south and west faces of the new tower where the gablets sit above balconies. There are two of these on each side with the exception of the side facing the roof (north). Shown below, being worked on in the carving shed, are three pieces of the gablet.
Ruben Gibson cutting springer – Photo Robert F. Rodriguez
Eddie Pizarro carving quatrefoil
Angel Escobar – Photo Robert F. Rodriguez
“We assembled this gable (or gablet, some would say) on the ground to show the public what it was we were working on. From the street level, all people could see were stacks of stone. We also assembled this to help raise money. There was a need to display not only apprentices at work, but a finished product.”
– Joseph Kincannon
Stacks of stone – Photo Robert F. Rodriguez
Special thanks to Joseph Kincannon for this information
Maybe you don’t read blueprints very well. Maybe two dimensional perspective sketches aren’t quite good enough. Well how about a very large scale model of the Cathedral that you can walk inside? Oh yes, now you see it. That is what Heins and La Farge created so that there was no mistaking what their design would look like.
From the December 1900 issue of Carpentry and Building Journal, comes this article. The finished model was displayed in the Leake & Watts building lobby on the Grounds.
“We understand that arrangements have been made for a public exhibition this winter of a complete model of the Cathedral of St. John the Divine, now in progress of erection on Cathedral Heights, New York City. The model will be of plaster supported on wood and iron frame work, with sheets of matting for the purpose of keeping the walls firm. The model will be about 50 feet by 25 feet in plan and 35 feet high. It is said that there will be room for 100 or more people to walk inside, and that the architects, Heins and LaFarge, have worked upon this model for nearly two years. The model will be exhibited on the site of the cathedral, and probably small fee will be charged.”
Interior of Heins and La Farge model
This view is of the interior of the model. It is looking towards the Altar past the Choir area from the future Crossing. The work is highly detailed inside and out.
Carpentry and Building Journal, December 1900
All Photos – Irma and Paul Milstein Division of United States History, Local History and Genealogy, The New York Public Library. 1900. Manhattan: Amsterdam Avenue – Cathedral Parkway
For reference, the Belmont Chapel, later named the Chapel of St. Saviour, began construction at the eastern end of the Cathedral around 1901 (left side of photo). 1899 saw the completion of the great eastern arch (right side of photo). The massive chancel columns were in place at the end of 1904 (center of photo). The picture above shows the choir walls beginning to go up. Cut stone production was in full swing at this time in the first stone shed.
Cutters and Carvers in the early stone shed
The massive columns defining the Chancel had to be up before the construction of the walls could begin. Once in place, at end of 1904 the walls of the Choir began to go up. The substructure of the walls was granite with the interior facing specified as Frontenac Limestone.
Beginning in 1901, the cutters and carvers created the stone that would decorate the interior of the choir, chancel, including the capitals for those massive columns and for work to continue to finish the first apsidal chapel, the Belmont Chapel. We don’t know the names of these cutters and carvers, nor the masons who set the stones. Their work and the beauty and craftsmanship is there for all to see.
Masons setting stone in interior of choir
As the stone was prepared, the masons began to set it.
The Sculptors Moved In
Slowly the carvers and sculptors took over the stone shed. They would create the statuary inside and outside the Cathedral. The photo below shows the models for the statues of the apostles. The final placement, high up on the outside walls of the choir, would show off these statues to the world.
Sculptors also carved the reredos for the altar in the stone shed.
Partially carved statues for Reredos alongside models – 1909
Frontenac Limestone was selected by Heins and La Farge from hundreds of samples submitted. It was quarried in Goodhue County, Minnesota along the Mississippi River. It is pale yellow to light cream in color and was used in much of the interior of the Choir, Chancel and Apsidal Chapels. The quarry began production in the 1850’s aided by river travel and slowly ceased operation in the beginning of the 20th century when river commerce was overtaken by the railroads.
All Photos – Irma and Paul Milstein Division of the United States History, Local History and Genealogy, The New York Public Library
