Uploaded March 2020 | Updated September 2026, 2 weeks ago
The astronomical clock contains well over a thousand screws. Each needs to be blued to a uniform color. There are also a large number of other parts that require the same treatment. So Buchanan came up with a precision oven to do this in a more efficient way than to do each part over an open flame. It is an aluminum block with two electric elements inserted in it and a precision temperature controller inside an insulated box, with a glass lid. Now one can flick a switch and in a few minutes know the temperature will be correct and it will always be consistent. With the glass window it is also draft proof. There is also no time issue to prevent the part from being overheated. This is the reason parts blued over a flame or in brass filings held over a hotplate need "quenching" in water or oil to stop the process quickly. Furthermore this setup makes the bluing of long pieces like clock hands far easier since the heat is even over the entire length of the part. In the oven there is no hurry, once one knows the correct temperature the parts will blue to the desired color no matter the time in the oven.
The astronomical clock contains well over a thousand screws. Each needs to be blued to a uniform color. There are also a large number of other parts that require the same treatment. So Buchanan came up with a precision oven to do this in a more efficient way than to do each part over an open flame. It is an aluminum block with two electric elements inserted in it and a precision temperature controller inside an insulated box, with a glass lid. Now one can flick a switch and in a few minutes know the temperature will be correct and it will always be consistent. With the glass window it is also draft proof. There is also no time issue to prevent the part from being overheated. This is the reason parts blued over a flame or in brass filings held over a hotplate need "quenching" in water or oil to stop the process quickly. Furthermore this setup makes the bluing of long pieces like clock hands far easier since the heat is even over the entire length of the part. In the oven there is no hurry, once one knows the correct temperature the parts will blue to the desired color no matter the time in the oven.
