Erich Weidenhammer
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eweidenh.bsky.social
Erich Weidenhammer
@eweidenh.bsky.social
2K followers 1.7K following 93 posts
Scientific Instruments at the University of Toronto
Material culture & SciTech heritage
Sundry 3D printing and design
He/Him
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eweidenh.bsky.social
A similar mount for this locally developed "Toronto" mercury lamp from the 1950s- a monochromatic light source for spectroscopy. 3d-printed vertical pieces have channels for fishing line to secure the artifact, which is very front heavy due to the mercury. Do not drop.
#Histsci #3dprinting
A glass instrument mounted, a low pressure mercury lamp, on a white stand. The instrument consists primarily of two interconnected mercury-filled bulbs with appendages for electrical leads and the attachment of a water supply to the internal cooling channels. A narrow, tubular section is presumably where the incandescing mercury vapour supplies the light. At four points along this tubular section, the artifact is cradled in the stand and secured with clear fishing line.
October 9, 2025 at 5:31 PM
eweidenh.bsky.social
I'd love to know the story behind the deep scorch marks on this handcart from the old geophysics program.
#HistSci #artifact
An very old, very worn handcart marked "GEOPHYSICS". The bed is formed by wooden planks. It has a sturdy metal handle. There are several deep scorch marks in the upper half of the wooden deck.
October 6, 2025 at 2:50 PM
eweidenh.bsky.social
These are straightforward to make. The base is a length of MDF baseboard. The 3d-printed guide and 3/8" bit shown here is used to make holes for mounting lengths of hardwood dowel. You glue the socketed, 3d-printed element onto the dowels. This arrangement is standard across several mounts.
Photo shows a cordless drill with a 3/8" wood bit mounted. It also shows an unpainted length of MDF baseboard with a 3d-printed jig. The jig has two holes to guide the drilling of holes to mount lengths of dowel. A length of 3/8" dowel has been placed on the piece of baseboard.
October 3, 2025 at 6:49 PM
eweidenh.bsky.social
Here's a pretty basic reinforced mount. I made three of these to support a long and delicate '60s He-Ne laser that forms the top edge of the glass-themed display. That thing was not easy to get into place past all the supporting wires.
#histstm
A close image of a white mount placed on a white exhibit shelf. The mount supports one end of a long and narrow glass instrument. It is cradled in a concave element/ An overall view of a long glass He-Ne laser held in three similar mounts.
October 3, 2025 at 6:34 PM
eweidenh.bsky.social
Cases and shelves are white. I tried to colour match the mounts to the cases and to keep the shapes simple and rectilinear so that the artifacts stand out.
A glass display case, built into a wall, containing several adjustable white shelves. Columns of shelves are mounted on vertical cables, with one cable passing though each corner. The shelves contain glass artifacts, several of which are cradles on custom made white mounts.
October 1, 2025 at 10:47 AM
eweidenh.bsky.social
I've been making various artifact mounts for a forthcoming science exhibit. These are basic 3d-printed fixtures, often mounted on lengths of MDF baseboard and reinforced internally with dowels. Thought I'd share some tips and solicit suggestions.
#histsci #histtech #3dprinting
A series of white-painted artifact mounts of various sizes and shapes arrayed on an extremely red table.
October 1, 2025 at 10:47 AM
eweidenh.bsky.social
It's a nice example, with a full set of accessories as well as forms and an instruction booklet. Unfortunately (like many artifacts of this era) the plastic foam lining of the testing chamber is decomposing badly. It took a lot of careful cleaning as the remaining material is very fragile.
This photograph shows the testing chamber with the lid open before cleaning. Pieces of brittle foam surround the integrated microphone within the chamber. This photograph was taken before the chamber was cleaned of loose material, but after the various accessories that had been stored in the chamber were removed. Those took a lot of cleaning as they were contaminated with bits of rotten foam.
June 24, 2025 at 10:25 AM
eweidenh.bsky.social
Back in 2017, we collected this early '80s portable hearing aid analyzer from the old Queen Elizabeth Hospital/ Toronto Rehab. This was, apparently, the first of its kind—built into a suitcase with an integrated testing chamber.

utsic.utoronto.ca/wpm_instrume...

#DisHist #histmed #sts #UTartifact
A photograph of an FP20 Portable Hearing Aid Analyzer, a microcomputer-controlled instrument introduced in 1982. The unit is housed in a standard black Samsonite briefcase. This is open in this photo revealing the white-coloured console of the unit and the testing chamber. The lid of the testing chamber is closed.
June 24, 2025 at 10:25 AM
eweidenh.bsky.social
At some point in the late 60s or early 70s, work began on a plastic femoral implant to match the MacIntosh tibial plateau. Besides a 1977 patent, there is little documentation about this work. The collection has several interesting experimental pieces.
utsic.utoronto.ca/wpm_instrume...
This image shows a prototype partial knee as depicted in a 1977 US patent assigned to the University of Toronto. One the left is a plastic (likely high density polyethylene) femoral component. One the right is a metal (likely Vitallium) tibial plateau.
June 10, 2025 at 5:55 PM
eweidenh.bsky.social
This development emerged from the MacIntosh knee, an early tibial implant used to correct valgus and varus deformities due to arthritis. The first example was implanted in 1954. The design evolved for years and was widely used. That history can be found here:
utsic.utoronto.ca/wpm_instrume...
This image shows a collection of six MacIntosh implants of various sizes that are catalogued within the Jackson collection. Each implant is a metal piece that replaces the bearing surface of one condyle of the tibia. The photo shows the highly polished upper surfaces of the implants. The lower surfaces are textured to ensure a friction fit against the underlying bone. The MacIntosh implant was uncemented. This image is taken from p. 248 of MacIntosh and Hunter 1972. It shows a series of four photos. The first is an image of a patient's legs with varus deformity due to osteoarthritis. The second image is an x-ray photo of the arthritic knee. The third image shows the corrected knee. The fourth image is a x-ray photo showing the MacIntosh implant in place in the corrected knee.
June 10, 2025 at 5:55 PM
eweidenh.bsky.social
I was grateful to meet with Dr. Robert Galway (beard), a retired Toronto orthopedic surgeon. We examined some curious prototypes of an artificial partial knee developed at Toronto General and the U of T. It was never produced. Only a few people alive know anything about it.
#Histmed #OrthoSky
A photograph of Dr. Peter Kopplin (left) and Dr. Robert Galway (right). They are standing in front of a table that holds an array of artificial knees and related items. These are arranged in chronological order. Dr. Galway was on staff at Toronto general when some of this development took place. Although he wasn't directly involved, he knows several people on the orthopedic community who may have some information.
June 10, 2025 at 5:55 PM
eweidenh.bsky.social
There are also two different English-made adaptations of the Judet hip in the Jackson collection:
utsic.utoronto.ca/basic-search...

I'll recatalogue the Buton model ASAP; For some reason there was (what's likely) a MacIntosh ceramic knee plateau in its box. ¯\_(ツ)_/¯
This image shows an English-manufactured version of the Judet hip prosthesis called the Newman's Hip Prosthesis. It is different from the Judet model in having a broader and more rectangular aspect to the lower portion of the head that fits like a collar over the remaining portion of the femoral head. The information sheet included in the box with this item notes that it is made of a Perspex (acrylic) that is manufactured without plasticizer. This image shows the Buxton's model of the Judet hip. It is similar to the Newman's model, but with a shorter collar below the head and a slightly different profile to the step. The image also shows what's probably a MacIntosh knee plateau prosthesis that was mistakenly catalogued with the hip because it had been placed in the same box.
May 21, 2025 at 10:42 AM
eweidenh.bsky.social
Robert W. Jackson, who collected these, is celebrated for introducing the Watanabe arthroscope into the mainstream of orthopaedics. This was a revolution in knee surgery, reducing healing times and improving outcomes. His collection includes many Watanabe items.
utsic.utoronto.ca/basic-search...
This is a black and white image showing Dr. Robert W. Jackson in surgical garb examining the interior of a patient's knee with a Watanabe arthroscope. The arthroscope is about the size of a fountain pen. It has a wider eyepiece on one end that Dr. Jackson is looking into.
May 21, 2025 at 10:42 AM
eweidenh.bsky.social
Here's an acrylic prosthesis collected by Toronto surgeon Robert W. Jackson. The Judet hip was first implanted by the French brothers Robert & Jean Judet in 1946. Their Parisian clinic became a popular stop for surgeons learning the technique.
utsic.utoronto.ca/wpm_instrume...

#Histmed #OrthoSky
A side view of a clear plastic hip implant with a vaguely mushroom-like form consisting of a partially hemispherical head (taking the form of the head of the femur) and a narrow stem, which is implanted into the neck of the femur. Visible within the clear stem is a metal rod that provides reinforcement and x-ray visibility. Visible within the head are metal x-ray markers for locating the prosthetic in an x-ray image. Portions of the interior of the head are cloudy, possibly due to deterioration with time. There is a chip in the lower edge of the head. A front view of the Judet hip prosthesis giving a clearer view of the x-ray markers embedded in the acrylic head.
May 21, 2025 at 10:42 AM
eweidenh.bsky.social
Tangentially related: The other day, Kristen den Hartog gave a wonderful presentation about her new book "The Roosting Box", a history of the Christie Street Military Hospital. It was established as the Toronto Military Orthopaedic Hospital in 1919 to treat disabled soldiers of the First World War.
This image shows a projected slide from den Hartog's presetation that depicts a black and white photo showing craftspeople (two women and a man) seated in a workshop creating facial prosthetics for disfigured veterans. The photo is credited to the U of T archives. To the right of the projector screen den Hartog at a lecturn in front of a microphone.
May 17, 2025 at 9:48 AM
eweidenh.bsky.social
There's a lot to uncover about how these bone and ivory items were made and distributed, and by whom. There's not a lot written. Certain items, especially the fine nails and bone plates, are reminiscent of Inuit ivory craft work.

Grateful for ideas and suggestions!
#Histmed #MedSky #OrthoSky
A close view of two bone or ivory bone plates and a partly finished section of cow bone. The plates are elongated with rounded edges. The plates have countersunk holes in them to accept bone or ivory screws. One is narrower and has four holes. The other is wider and has three. The narrower of the two plates is marked with the word "Germany".
May 15, 2025 at 10:17 AM
eweidenh.bsky.social
These came from the celebrated Canadian orthopedic surgeon Dr. William E. Gallie (1882 – 1959). Gallie's work on bone fractures mentions the use of boiled cow bone plates and screws applied experimentally to fractures in dogs. Over time, the cow bone was reabsorbed into the healed fracture.
This is a bad scan of an illustration from Gallie and Roberson's 1919 long paper, "The Repair of Bone". It shows a fractured radius of an adult terrier, repaired with boiled cow bone plate and screws, and resected after 8 weeks of healing. The implants have been absorbed into the living bone. (Fig 250, p. 237).
May 15, 2025 at 10:17 AM
eweidenh.bsky.social
Here's an interesting little collection that was donated by Dr. Allan Gross of Mt. Sinai hospital when I stopped by for help identifying some prosthetic joints. These are various early 20th implants made of cow bone and ivory.
They are catalogued in detail here:
utsic.utoronto.ca/wpm_instrume...
This is an overview of an image showing eighteen small artifacts. Some are made of cow bone, others may be made of ivory. Three are larger pieces of boiled cow bone. These were likely used to demonstrate the process of making the finished items. (The outline of a bone plate is traced onto the surface of the largest piece). Finished pieces include two bone plates of different sizes, three screws, three intramedullary pegs, and six narrow pins. The craft work items is impressive; The screws are only a few millimeters in diameter, but have fully carved threads.
May 15, 2025 at 10:17 AM
eweidenh.bsky.social
I say “scanned”. I really just took about twenty camera phone photos and ran them through Meshroom to play with photogrammetry. This wasn’t enough information for a good result, so I had to fix and redraw much of the mesh in Blender. It was tedious, but I got to practice the sculpting process.
A screen grab of the unedited mesh generated by Meshroom and imported into Blender. It is very incomplete and messy.
January 15, 2025 at 11:46 AM
eweidenh.bsky.social
Here is the original. I guess he’s generally known as "Le bonhomme qui tient la maison." My kid was potty training during a recent visit so he was temporarily renamed “Le bonhomme qui fait po-po.”
A photo of the original gargoyle--a stylized medieval knight in armour on a sort of pillar as part of the decoration of an interior doorway.
January 15, 2025 at 11:46 AM
eweidenh.bsky.social
I made these little shadow boxes to display printouts of a scanned plaster gargoyle from my in-laws' house in SW France. They're for my brothers-in-law as mementos of the house they grew up in. I've spent a fair amount of time there with my family over the years.
Two identical shadow boxes, panted brown and black, each contain a white 3d-print of stylized knight gargoyle. These was made from a scan of an original plaster detail that's on a doorway in my in-law's house. A close up of one of the shadow boxes to better show the print.
January 15, 2025 at 11:46 AM
eweidenh.bsky.social
We had a lovely visit last week from a group heading to the Scientific Instrument Commission conference in Ottawa. We took them around and showed them some stuff.
#HistSci #HistSTM
September 21, 2024 at 5:41 PM
eweidenh.bsky.social
An interesting artifact from the history of geophysics: an undersea surveying instrument from the 1980s developed to study the the seafloor using the magnetometric resistivity (MMR) method. Richly catalogued!
utsic.utoronto.ca/wpm_instrume...

#museums #histsci #histSTM #earthsciences
The MOSES receiver in its shipping case. The case is about (64cm x 57cm x 57cm) when closed. The main central plate of the instrument nearly reaches the inner edge of the enclosure. It's pretty big. Two fluxgate magnetometer sensors adapted from Scintrex MFM-3 magnetometers are mounted orthogonally above a central aluminum plate. A large computer mainboard was probably mounted on the plate. This, unfortunately, was removed at some point. A black and white photo showing the MOSES receiver mounted in a spherical enclosure that is attached to a large tapering concrete anchor. This will carry the assembly to the seafloor. Various radio transponders are attached to the enclosure to permit the recording of its location relative to the research vessel and to facilitate its recovery once freed from the anchor. This assembly is seen suspended above the ocean surface prior to release from the Canadian survey ship Vector.
May 30, 2024 at 12:42 PM
eweidenh.bsky.social
I think we can consider the mid 20th c. to be the era of pretty electronics.
The analyzer element of a Coulter Cell Sorter with its lid off, revealing the electronic components inside. The interior of a deaccessioned turbopump controller from Chalk River National Laboratories showing various colourful electrical components. A pair of DC amplifiers from the University of Toronto Engineering Psychology collection. Its surface is covered with various dials and colourful terminals.
October 12, 2023 at 9:55 AM
eweidenh.bsky.social
We acquired two very long (~2m), very delicate glass helium-neon lasers that were hand-made made at the U of T Physics department in the 1960s.

I put together a storage mount of 3d-printed cradles mounted on a pine board.
A long glass artifact (a laser tube) mounted to an unfinished pine board. The artifact consists primarily of a narrow glass channel with three larger cylindrical bulbs. The bulbs have wire leads emerging from them. A close-up view of one a bulb at one end of the tube. This image shows the 3d-printed cradle, screwed to the pine board, that supports the artifact.
October 6, 2023 at 7:15 PM