Summary
• TMJ Interiors has worked on many notable historic building restorations.
• The ceiling was designed and manufactured in more than 2,500 separate pieces.
• A Reichenbacher Vision Sprint CNC machining centre was used for the vast majority of the manufacture.
• The grain of the oak was evaluated to plot optimum cutting paths.

Taylor Made Joinery Interiors Ltd has further enhanced its reputation as a joinery manufacturer by undertaking the design, manufacture and construction of a magnificent

fan-vaulted ceiling for the new tower of St Edmundsbury Cathedral in Bury St Edmunds. The spectacular oak ceiling, due to be completed this year, will be the crowning glory for the Gothic revival tower, built as part of a millennium project.

Suffolk-based TMJ Interiors has an impressive track record of successful historic building projects, notably the restoration of Windsor Castle following the devastating fire in 1992. The company has also completed high profile projects at the Tower of London, 10 Downing Street, the Royal Festival Hall, the Royal Shakespeare Theatre, the Royal Opera House and the Guildhall in London.

Laser cloud survey

In April 2008, having received the project brief from Freeland Rees Roberts Architects, the TMJ design team began working on the detail and structural elements of the ceiling. A laser cloud survey of the inside of the historic tower measured 29 million points, enabling designers to model the existing structure accurately. The data was imported into a 3D computer software program where precisely detailed working drawings and five-axis tool path drawings were created.

Due to its sheer size and the complexity of the construction, the ceiling was designed and manufactured in over 2,500 separate pieces, with a total weight in excess of five tonnes. The large oak structural frame, comprising eight curved rib sections with a central circular assembly, was initially erected at TMJ’s workshops. All ornamental openwork was applied and the complete ceiling was built up prior to installation. Timber used for the project had to be sympathetic with the fabric of the building and be both hard-wearing and durable; for these reasons TMJ opted for solid FSC-certified European oak.

Reichenbacher CNC

TMJ couldn’t have taken on this type of construction challenge unless it was totally confident in the joinery know-how of its craftsmen and the outstanding accuracy and robustness of its CNC machining capability. Components for the project were precisely machined using a Reichenbacher 5-axis CNC machining centre. To increase the strength of the oak components and also minimise waste, a laminating process was used, which involved layering up various sized timbers to create suitable workpieces for machining.

TMJ operates two Reichenbacher 5-axis CNC machining centres; a Univers and a Vision Sprint, and it was decided to use the latter for the complete manufacture of all the components, with only some detail finishing and final assembly being carried out by hand.

‘‘The Vision Sprint has remarkable manoeuvrability in three dimensions and is capable of machining the most complex components,” said David Clarke, TMJ’s CNC specialist, who created parametric programs for each component. “Even very large pieces with double curvatures and extremely tight radii didn’t present a problem for the Vision. With the need for ‘all-round’ machining, we had to make jigs in ply or MDF for every single component and we carefully evaluated the grain of the oak to plot optimum cutting paths and to select the best possible tools.’’

The 5-axis Vision Sprint features two rotary axes, which are inclined at 45º to each other and optimised to intersect their centre axes at the working point of the tool. This means that highly efficient three-dimensional machining is achieved with fewer interpolated movements.

Quality and accuracy

The quality of finish and accuracy of all the ceiling components was first class and this was proven when it came to constructing the ceiling in the workshop – all fixings were at the correct angles and everything fitted together perfectly. The whole structure was then dismantled, transported to the Cathedral, and hoisted over 30m for installation within the tower. When completed, the vaulted ceiling will be gilded and painted blue, green and red.

Speaking about the project, co-founder and managing director of TMJ Interiors James Taylor said: “This is a perfect example of Reichenbacher CNC technology and traditional craftsmen working together to complete a stunning masterpiece.

“We are helping to create a piece of history and are hugely proud of the now almost finished result. This is an incredibly solid but decorative piece of oak sculpture which has been created by pushing the very boundaries of structural and decorative joinery.”

• An article on the architectural and structural aspects of the St Edmundsbury Cathedral ceiling appeared in TTJ sister title, Timber & Sustainable Building Autumn 2009 www.timber-building.com.