Rose Engines: The Preferred Machine for Guilloche

I was very pleasantly surprised to see that the brief blog posting on Engine Turning, Jeweling, and Guilloche was the most popular post last week.  It seems that others share my fetish for these interesting decorative machine arts.  As a result, I wanted to share a couple of great videos that really show how Guilloche (that’s pronounced “Gee-o-shay”) is done with a machine called a “Rose Engine”.  Perhaps the idea that a Rose Engine is used results in the use of the term “Engine Turning” for Guilloche.  I like that latter term better.  It’s more elegant and Engine Turning has become firmly entrenched in many minds as being the little abrasive circles that appear on metal.  I will take this opportunity to apologize for not using the proper accent on the term Guilloché, but it is just easier to type without it and the use of the term without it appears to be commonplace on the Internet.

Our first video is from a fine watchmaker that hails from right here in the good old U. S. of. A.  Roland G. Murphy makes spectacular hand-crafted wrist watches, and their video is also extremely well done:

As you can see from the video, Guilloche is done with a machine that’s more like a very specialized shaper than a lathe or milling machine.  This results in the markings on the material having a much different character and a lot more texture.  In addition, these old machines are entirely hand powered.  They use cams (called “Rosettes”) to give the workpiece a periodic “wobble” that results in the distinctive curves and curlicues that are characteristic of Guilloche.  If you watch closely, you can see that the operator has to manually start, stop, and position the cutter to keep the design within the outline it is bounded by.

Here is another great video from the great old watch maker Vacheron Constantin:

It’s a little less technical but no less fascinating to watch this fine art form being done my VC’s “Master Guillocheur”.  There are some great closeups showing the shaper-like tool peeling chips off of watch faces.

Here’s a last one, in the spirit of fine watchmaking of the other two:

I believe this video is from Victorinox, and there are some fascinating insights to be found in it.  The discussion of how the Guillocheur uses his sense of touch and visual indication of chip size and formation to create the best effect is wonderful.  Also note that this Rose Engine has not only the normal Rosette cams, but an additional cam at right angles that he uses to create more geometric patterns.  Heretofore I had associated Guilloche primarily with curves, but we can see this is not a requirement.

Looking at these wonderful old machines, my first inclination is to dive into creating a software simulation of a Rose Engine that could be used to create g-code for a CNC.  Simulating the motions of the machine and allowing the creation of the Rosettes from perhaps DXF files would be straightforward if complex and voluminous.  It would be a fascinating project for me, but one that will have to wait a while as there are more pressing commercial realities for CNCCookbook!