Wire and Cardboard Escapement Mechanism


Moments after I took this video the escapement stopped. Then I made “improvements” which made it worse. Likely the whole thing needs to be scrapped but it only took me 30 minutes to make so no big deal. You can’t get too precious with cardboard.

Endowed birds

Birdhouse on the Ayazma Camii Mosque. Istanbul, Turkey. Photo by Celalettin Güneş

Birdhouse on the Ayazma Camii Mosque. Istanbul, Turkey. Photo by Celalettin Güneş

The photo above is a two centuries old birdhouse crafted with the same care and skill as the stonework of Ayazma Camii (Holy Spring) Mosque on which it clings.

From theromantictraveler

The charters for new mosques often included provision for feeding the birds that lived in these shelters. The Beyazit II mosque in Istanbul, built in the late 15th century, had a charter that allocated 30 pieces of gold each year to look after its birds. Even when the charter was eventually revoked in the 1920s the official then in charge of the mosque continued to feed them out of his own salary until 1947. In the great Dolmabahce Palace there’s a room that was devoted to looking after sick and injured birds.

Fazil Husnu Daglarca, the famous Turkish poet, relates how a man in Sivas used the income from two shops to look after the city’s birds, and all across turkey you come across similar endowments. In Islam there’s a tradition, at least there used to be, of endowments for everything from poor kitchens, fountains, homes for widows and alms for orphans to trousseaus for poor girls and books for libraries and colleges. Endowments providing water and grain to birds and other animals were just a part of this enlightened attitude.

You can also see more photos on a recent post at Islamic Arts and Architecture.

Hat tip (again) to Dr. Stephennie Mulder.

Cardboard Gears Go

It worked in theory and it seems to work in practice too.

Work continues on the Super Simple Clock.

I had been pondering the best way insert bushings into cardboard for days when it came to me while I was putting on my daughter’s shoes — grommets! A little sanding with 220 grit on the 1/4″ dowel and it runs quite nicely. I’d didn’t have any 1/8″ dowel on hand but to my delight, I found that bamboo skewers are a remarkably consistent 0.005″ less than 1/8″.

The double thickness of Cheerios box may be a bit of challenge to cut for 10-year-olds, but with sharp scissors and some determination I really think they can do it. They’re too young for carpal tunnel syndrome right?

Super Simple Gear Geometry

This June I’ll be teaching a summer camp class to 4th and 5th graders titled “Gears and Gravity.” In my proposal I claimed, “We will explore the history and science of time keeping (horology) by hands on experimentation with simple machines and then construct our own real working mechanical clocks from paper and wood.” Now I have to design said clock.

My first challenge is to design a gear train (“going train” in horology parlance) with the simplest possible tooth profile that is easy to cut out and error tolerant.

Did I mention that my class budget is $125?


On the cover of Sculpture Magazine


In December of 2011 my UT colleagues and I collaborated with artist Diana Al-Hadid to fabricate a large scale sculpture commissioned by UT Visual Arts Center. I learned recently that this sculpture, “Suspended After Image,” is featured on the April cover of Sculpture Magazine. The portion that we fabricated with our CNC router is the bluish “cloak” on the left which I also posted about here and here. Hook’em!

Rolling censer

Pierced globe Incense Burner, Mamluk period (1250–1517), late 13th–early 14th century Syria, Damascus. British Museum.

Pierced globe Incense Burner, Mamluk period (1250–1517), late 13th–early 14th century. Syria, Damascus. British Museum.

Zayn al-Din. Incense Burner or Handwarmer. 15th - 16th c. gilded brass with silver inlay. Walters Art Museum.

Zayn al-Din. Incense Burner or Handwarmer. 15th – 16th c. gilded brass with silver inlay. Walters Art Museum.

Knowing my interests, my friend and remarkable scholar, Dr. Stephennie Mulder sent me the image of the gimbaled censer above. The link to the British Museum (which seems to be dead now) stated that the gimbals keep the incense cup from spilling its contents while swinging but this seems overly fussy to me considering the centrifugal forces of swinging itself solve that problem.

Another site suggested that these type of censers were used in games and rolled from one guest to another. I suppose this would work if it were a very low impact game but any amount of velocity or impact and I think the host’s carpet would suffer some damage from errant embers.

The description of “hand warmer” makes a lot more sense to me. In this case the mechanism would function perfectly. Unfortunately, I can’t confirm that the Walters object is also gimbaled though it must have some kind of suspension for without it the orb would certainly be too hot handle with bare hands.

All these pragmatic issues aside, both of these objects are virtuosic expressions of master metal smiths and are a delight to they eyes. What a pleasure it would also be to hold one of these in my hands!

Inverted Geneva Wheel Mechanism


Over a year ago I created this lively little mechanism and just tonight got around to drawing up the plans for it. In addition to the jpg above I have also uploaded a PDF to my public Google Drive.