I want to thank everyone for the comments and links related to shrinkage during during the metal casting process. I apologize for not having time to respond to the comments or investigate the sources thoroughly at this point.
The take-away point I'm getting is that size decrease is inevitable during metal casting. A given mass of metal will have a greater volume when molten then when solid, so the metal piece that is produced from a mold will be smaller when cold than the mold it filled up when molten. There is also the potential for molds made of ceramic to shrink while when they are produced.
Anyway, it appears that it's perfectly logical to expect a trend of decreasing size if a series of objects that was produced through a "chain" of copying. The first generation will be smaller than the original; the second generation will be smaller than the first, etc. The sources several of you provided suggest about 1-2% size difference between the mold and the cast is typical of copper alloys.
The take-away point I'm getting is that size decrease is inevitable during metal casting. A given mass of metal will have a greater volume when molten then when solid, so the metal piece that is produced from a mold will be smaller when cold than the mold it filled up when molten. There is also the potential for molds made of ceramic to shrink while when they are produced.
Anyway, it appears that it's perfectly logical to expect a trend of decreasing size if a series of objects that was produced through a "chain" of copying. The first generation will be smaller than the original; the second generation will be smaller than the first, etc. The sources several of you provided suggest about 1-2% size difference between the mold and the cast is typical of copper alloys.
I took a few minutes and gathered some metric data from the three swords I've got in my office (California, Italian eBay, and Design Toscano). I defined seven landmarks (labeled A through G on the diagram) that I could reliably locate on all three swords. I used dial calipers to measure the straight line distances between four pairs of landmarks. Here are the raw data:
The larger size of the Hercules on the California sword shows up in all the dimensions. The Design Toscano sword in the smallest. The Italian eBay sword is in-between. That supports a chronological ordering with the California sword earliest, the Italian eBay second, and the currently-produced Design Toscano sword latest.
If these three swords represent different generations, how much size decrease was there between generations? I calculated the differences (in both millimeters and percentages) of the measured dimensions of two pairs: (1) the California sword (Sword 3) and the Italian eBay sword (Sword 4); and (2) the California sword and the Design Toscano sword (Sword 5). Here are those data:
If these three swords represent different generations, how much size decrease was there between generations? I calculated the differences (in both millimeters and percentages) of the measured dimensions of two pairs: (1) the California sword (Sword 3) and the Italian eBay sword (Sword 4); and (2) the California sword and the Design Toscano sword (Sword 5). Here are those data:
The measured dimensions vary from 0.8% to 4.2% between California and Italian eBay, with a mean difference of about 2%. To me, that seems most consistent with California and Italian eBay being representatives of sequential generations. Maybe the generation of the J Type swords was just once removed from the generation of the F types (in other words, an F Type sword was used as the model for the J Type, replacing the partially fullered blade with a shorter, unfullered blade).
The differences between the California sword and the Design Toscano Sword vary from 5.6% to 11.1%, with a mean of about 7.8%. Assuming a 1.75% decrease in size per generation, the Design Toscano sword could be fifth or sixth generation (with the California sword being "Generation 1"). A fifth generation sword would be expected to be about 93% the size of a first generation sword, assuming each generation is 98.25% the size of its parent.
I think the Cvet sword, the Spain sword, and the sword currently for sale on eBay (from Florida) could be members of a generation between the Italian eBay sword and the Design Toscano swords. These swords appear to be copper alloy swords with relatively "clean" blades missing the suite of anomalies that we're using to define the J Type. I've been calling this grouping "Type CS" in my head. If my hypothesis is correct, the dimensions of the Hercules on the Cvet sword should fall between those of the Italian eBay sword and the Design Toscano sword.
The differences between the California sword and the Design Toscano Sword vary from 5.6% to 11.1%, with a mean of about 7.8%. Assuming a 1.75% decrease in size per generation, the Design Toscano sword could be fifth or sixth generation (with the California sword being "Generation 1"). A fifth generation sword would be expected to be about 93% the size of a first generation sword, assuming each generation is 98.25% the size of its parent.
I think the Cvet sword, the Spain sword, and the sword currently for sale on eBay (from Florida) could be members of a generation between the Italian eBay sword and the Design Toscano swords. These swords appear to be copper alloy swords with relatively "clean" blades missing the suite of anomalies that we're using to define the J Type. I've been calling this grouping "Type CS" in my head. If my hypothesis is correct, the dimensions of the Hercules on the Cvet sword should fall between those of the Italian eBay sword and the Design Toscano sword.
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