During the last few weeks I have been working away on the last 5 flutes in my queue that I want to finish in October. I estimate that I have about 30 hours of bench time left on these. 2 of these are keyed and all have engraved rings and tuning slides. I am at the tuning and voicing stage. Afterwards, keys which are mostly ready to be mounted except for two that need to be made.
Some days and on weekends I have been working on the back addition to my workshop. This is a 12’ X 20’ uninsulated section that has my wood storage and tool graveyard. Until a week ago it was actually a dangerous space and largely inaccessible and looked like a hoarder’s nightmare. Now I have acres of open floor space, some 50 square feet of virgin bench top, and everything in there is accessible. It still needs to be sorted which I will work on a little bit each day.
This is in preparation for moving in the Gorton P1-2 Pantographic Milling Machine. I decided that this smaller one was sufficient for the outside profiling of my glass flutes. After the glass sections are bored and “reamed” out to dimension and finish, these will be mounted between centers on a small “wet” lathe mounted on the bed of the mill. Mounted in the spindle there will be a horizontally rotating diamond wheel set at the same center height as the lathe. The stylus will follow a 2X profile of the shape. The first cuts will barely touch the rotating glass rods at their widest points and the cuts will cut deeper and deeper until it is close to final cuts. Then a series of finer grit wheels will be used to bring it to final dimension. The glass will then be wet sanded and polished on a simple lathe using appropriate abrasives.
These machines didn’t exist in Laurent’s time. I am now 99% convinced that the bodies were largely blown into a mold, and then trimmed to length. The insides were ground using the same processes that I intend to use. One had to make sure that there was enough glass in the gather to allow for the correct wall thickness. Or the molds may have been oversize.
These could have been simply ground to diameter on a large horizontally rotating copper disk with abrasive slurry. These could have been purposely shaped to the specific outside shapes of the joints. Cast iron is used in the optics industry for rough grinding lenses to shape, and is relatively soft and easy to turn. Thus it may be possible to shape the glass this way and such setups are commonly available, but expensive! However, I am thinking that one could repurpose some cast iron pans and make a turn table. Am thinking of a speed reducer with the shafts at 90 degrees to each other that could be mounted to the lathe bed with an axle driving the horizontal shaft. The vertical shaft would have a simple faceplate setup mounted to the pan (with the handles removed, thank you). A 120 grit carbide slurry would coat the bottom of the pan and away we go. I actually have most of the parts for something like this and am about to check online for some larger cast iron pans.
The next post will probably be all about the mill, and moving it in.
(slightly later) This is almost perfect. The “seasoning” can be burned off with a torch. Its nice to have some sort of lip to keep the slurry from washing off.
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