The Sir John Bennett tower clock. / Photo by The Henry Ford.
The quarter-hour chime of the Sir John Bennett tower clock is a memorable sound that can be heard throughout Greenfield Village, emanating from its four figures—the muse, Gog, Magog, and Father Time (shown right to left above). Early in 2021, Magog’s chime and striking arm developed cracks along the mechanical shoulder.
Recorded damage of Magog’s chiming arm. / Photo by Andrew Ganem.
Disassembly of Magog’s arm prior to cleaning. / Photo by Andrew Ganem.
The arm was disassembled by Conservation Specialist Andrew Ganem, and conservation and curatorial staff were faced with a decision to repair the original arm or to replace it with a replica. One of the major concerns with repair was that new cracks could develop in the already thin (0.04”) sheet metal when Sir John Bennett becomes operable again. After some discussion, we made a decision to replicate and replace the arm to allow for safe operation of the clock, while preserving the original component in storage for future reference.
The replica arm could not be easily replicated using conventional copper metalwork techniques because of its highly textured surface. An easier replication method came from our partners at Ford Motor Company, who proposed the use of 3D scanning and polymer printing. To accomplish this, the original arm was 3D scanned and that data imported into a computer-aided design (CAD) program. The replica arm was then printed using stereolithography (SLA) 3D printing. You can learn more about this type of printing here.
Image courtesy Ford Motor Company.
Image courtesy Ford Motor Company.
Image courtesy Ford Motor Company.
The scanned model of the arm was produced by Daniel Johnson and Kevin Lesperance at Ford Motor Company’s metrology lab.
A side-by-side comparison between the SLA 3D-printed copy on the left and the original artifact on the right. / Photo by Cuong Nguyen.
The 3D-printed part is tested for fit prior to electroplating by Ford Motor Company’s Erik Riha on left and The Henry Ford’s Andrew Ganem on the right. / Photo by Cuong Nguyen.
The SLA plastic material wasn’t strong enough to endure continuous use in the outdoor environment of Sir John Bennett’s tower clock, so Ford engineers proposed coating the replica polymer part with nickel and copper layers using electrical deposition. The nickel layer stiffened the print, while the copper layer offered a better surface for painting.
Test for fitting the plated arm onto Magog. / Photo by Cuong Nguyen.
Holes in the cast iron mount for the arm. / Photo by Cuong Nguyen.
The use of an appropriate painting system that could endure the outdoor environment in Greenfield Village was imperative. Dr. Mark Nichols of Coatings, Surface Engineering, and Process Modeling Research at Ford Motor Company and Dan Corum of PPG recommended PSX-One (high solids, acrylic polysiloxane.) Amercoat 2/400 was used as a primer, as it provides chemical, environmental, and moisture resistance. The paint colors on the original arm were matched to a color sample and duplicated by Andrew Wojtowicz of PPG.
Original arm, left; 3D-printed arm, right; and Munsell color sample in the middle. / Photo by Cuong Nguyen.
The primed surface on the shoulder and elbow was coated with oil sizing and gilded with 24-karat gold.
Left to right: SLA-printed replica; copper/nickel/copper-plated SLA replica; copper/nickel/copper-plated SLA replica primed, painted, and gilded, ready for use; and original artifact part for comparison. / Photo by Cuong Nguyen.
During a test assembly, we noted that the linkage that connects Magog’s arm to the chiming mechanism was too short, so Andrew fabricated an extension and attached it to the original linkage. He also fabricated new hardware for the elbow joint to accommodate the additional thickness of the replacement part.
Extension fabricated by Andrew Ganem. / Photo by Andrew Ganem.
Photo by Cuong Nguyen.
Elbow joint. / Photo by Cuong Nguyen.
Original and machined hardware. / Photo by Andrew Ganem.
Magog’s clapper for the bell striker required attention by Andrew and The Henry Ford’s welder Chuck Albright, who soldered the joint between the cuff, wrist, and grip for the strike (hammer). A vibration isolator (made from Sorbothane) was inserted to reduce shock between the clapper and the arm during operation.
Separation between the hand and the wrist. / Photo by Cuong Nguyen.
Required surface preparation for a strong solder repair. / Photo by Andrew Ganem.
The size of the fist. / Photo by Andrew Ganem.
Special thanks to Dr. Mark Nichols, Dr. George Luckey, Erik Riha, Daniel Johnson, and Kevin Lesperance at Ford Motor Company, and to Daniel Corum and Andrew Wojtowicz at PPG. The help from Ford Motor Company specialists and their fabrication equipment made the project possible without invasive modifications to the artifact part.
We also extend a grateful thank you to Jason Hayburn, whose generous donation funded the electroforming of the replica.
McCormick-Deering Farmall Tractor, circa 1925 / THF179719
International Harvester introduced the first commercially successful row-crop tractor, the McCormick-Deering Farmall, in 1924. It represented a whole new approach to farming. Today we think of corn, cotton, soybeans, and other crops as being planted and harvested in long rows, but before the 1920s, farmers often planted crops in a grid pattern on smaller fields, which they cultivated using draft animals and a shovel plow.
As tractor usage increased, farmers were able to reduce the amount of land dedicated to housing and feeding draft animals. On average, farmers could re-purpose five acres of land for every horse that was no longer needed. This increase in usable land for farming provided a powerful incentive for farmers to own a tractor.
The McCormick-Deering Farmall was the first tractor to incorporate small, closely spaced front wheels that could travel between rows, and a high rear axle clearance to straddle the plants. It also included a power “take-off” unit to run machinery like the New Idea corn picker. International Harvester, with its Farmall tractor, overtook Ford Motor Company to lead the nation in tractor sales.
Before (above) conservation and after (below) 2019 conservation work, with the addition of the Farmall Cultivator No. HM-229 add-on kit and set of metal wheels.
In 2003, a team of volunteers, under the direction of a conservator, began the process of returning the tractor to its 1926 appearance. During this process, most of the newer Farmall red restoration paint layer was removed, as were F-20 parts that were not appropriate to the “Regular” model.
Most recently, we made the decision to retain the 1926 appearance and re-introduce the 1930s Farmall Cultivator No. HM-229 add-on kit, a compatible addition farmers could purchase. To do this, the tractor would need to be painted in appropriate colors. Luckily, our Curator of Agriculture and the Environment, Debra A. Reid, tracked down the manufacturer’s elusive colors: International Harvester Gray and Harvester Blue varnish enamel paint.
Harvester Gray was fortunately documented by Mark Stephenson at McCormick-Deering.com. The Harvester Blue was matched from residual paint on a gang beam that was hidden behind an installed cultivator part. The paint was compared with a manufacturer’s paint chart from the Wisconsin Historical Society.
The residual Harvester Blue paint on the Cultivator’s gang beam.
To aid in completion of this project, a copy of the manufacturer’s original instruction manual we obtained proved to be an invaluable resource.
Conservation volunteers Doug Beaver, Glen Lysinger, and Jim Yousman put on the cultivator rear track sweep attachment, supported by a high-lift pallet jack.
Conservation Specialist Andrew Ganem steers the tractor as it is towed by Exhibits Preparator Bernhard Wilson.
Logistics included towing the tractor to its display location at the museum and completing the rest of the assembly onsite in the museum; for ease of movement, the rubber wheels were used to maneuver the tractor into the museum.
Exhibit Preparators Ken Drogowski on the forklift and Jared Wylie on the floor remove one of the 40” x 6” rubber wheels.
The metal wheel gets mounted by Exhibits Preparators Jared Wylie and Neil Reinalda and Conservation Specialist Andrew Ganem.
The rest of the cultivator assembly, which includes gang beams, two rear spring teeth, and ten gang sweeps, was added after the tractor returned to the exhibit area. A set of 25” x 4” front metal wheels and 40” x 6” rear metal wheels replaced the rubber wheels. This process required a methodic approach to safely complete, using forklifts, straps, a watchful eye for concerns and risks, and general tools. Once removed, the set of rubber wheels were returned to collections storage.
This work could not have been completed without the help of staff from the collections management, conservation, curatorial, and exhibits teams at The Henry Ford, as well as our dedicated volunteers Glenn Lysinger, Doug Beaver, Jim Yousman, Larry Wolfe, Harvey Dean, Neil Pike, Deb Luczkowski, Maria Gramer, and Eric Bergman.
Check out the recently conserved tractor and a variety of other agricultural items in the Agriculture exhibit in Henry Ford Museum of American Innovation.
This is the third of a series of blog posts presented in conjunction with the traveling exhibition, Louis Comfort Tiffany: Treasures from the Driehaus Collection. The exhibit, consisting of approximately 60 artifacts, is on view at Henry Ford Museum of American Innovation from March 6, 2021, through April 25, 2021. The lamp shown here is from the collections of The Henry Ford and provides background on themes in the exhibition.
In preparing for the Louis Comfort Tiffany: Treasures from the Driehaus Collection exhibit, The Henry Ford’s curatorial department expressed interest in displaying a Tiffany Studios early floor lamp, circa 1900, from our collections. This lamp features a telescopic shaft and a dual wick kerosene burner for extra illumination.
Our Tiffany lamp (THF186213) as compared to images from Tiffany publications.
In Tiffany publications, the lamp rests on an outer cushion-textured base with six ball-shaped feet. However, the outer base from The Henry Ford’s lamp was missing, with no previous record of its existence when it entered our collection in 1966.
Discussions between Curator of Decorative Arts Charles Sable and conservators led to the decision to create a replica lamp base to ensure both historical accuracy and physical stability to the tall, rather top-heavy floor lamp. The completed object would provide viewers with a more accurate interpretation and the opportunity to experience the object whole, as it was originally designed.
It’s All about the Base
We embarked upon an effort to locate a similar base in museums or private collections to serve as a reference or pattern, to inform the creation of a replacement base—only to discover that the lamp is quite rare. So instead, I decided to create a model base using a CAD (computer-aided design) program, with the design based on photographs from Tiffany publications and auctions. The museum’s lamp was used as a physical frame of reference for measurements and comparisons in CAD. I reached out to several 3D-printing shops to determine if they could use my CAD design to generate a three-dimensional plastic base. Ultimately, the base was printed with the help and generosity of the additive manufacturing team at the Ford Advanced Manufacturing Center.
The above images are the CAD model of the base from different angles.
Ford Motor Company and its Advanced Manufacturing Center (AMC) offered their additive manufacturing expertise and capabilities. Their team includes Global Chief Engineer Mike Mikula, Rapid Prototype Subject Matter Expert Scott Gafken, Technical Leader in Additive Manufacturing Harold Sears, Additive Manufacturing Engineer Supervisor Jay Haubenstricke, and Supervisor Additive Manufacturing John Phillips.
Collaborative discussions with Scott Gafken revealed that the process would take about 24 hours, which included printing as well as model cooldown for handling. The EOS P770 was employed as an industrial selective laser sintering (SLS) printer and produced the print in Nylon 12 (also known as Polyamide 12 or PA12). The printing material was selected based on its ability to bear the weight of the lamp, and someday be a candidate for an investment casting, for the creation of a metal base.
The white image shows the Polyamide 12 print of the base at the Ford Advanced Manufacturing Center. The image with painter’s tape was taken during the process of painting the base. Achieving a finish that matched the original metal lamp required the application of several layers of paint. The image with only one small white section shows the completed base after gloss varnish was applied.
The bronze surface of the lamp was shades of brown with hints of red, orange, and green. These shades are similar to several paint colors: raw umber, chromium oxide green, sepia, burnt sienna, and yellow oxides. The colors were mixed into several formulations to closely match the patina (aged finish) of the lamp. Diluted paint was applied in layers to allow the variations in the tones to be seen. After discussions with the curator and members of our Experience Design department, we made the decision to leave one section of 3D-printed surface unpainted, to allow visitors to see it in the exhibit.
The replica base was painted with the actual lamp present to ensure a match.
Beyond the base, other aspects of our conservation treatment included the cleaning of the Tiffany lamp with a bristle brush and vacuum. Wet cleaning included a dilute blend of anionic and nonionic detergents in distilled water, applied with cotton rags and cotton swabs. Residual detergent was then removed with a distilled water wipedown.
A protective barrier of wax was introduced via hot wax application. The bronze surface was heated with a hot air gun and microcrystalline wax was applied and left to cool down. A boar-bristle brush and bamboo picks were used to remove excess wax. The brush and cotton rags were then used to buff the wax layer, resulting in a uniform sheen.
Details of the lamp both before cleaning and after cleaning and wax application.