iron ignot?

Mark · 19th July 2007, 02:39 PM

Ric,

Are ingots (wootz or not) polygonal like this, at least sometimes? I recall seeing a couple facetted ones on Artzi's table at the Timonium show a few years back. Such a polygon would not, I think, work very well as a mill ball as it would have a reduced area of contact with the ore, and would not roll around as well. Whatever it is, I expect that the shape allows them to be packed more tightly, and/or stacked more stably.

Jeff Pringle · 19th July 2007, 04:38 PM

The grinding media used in ball mills can have a faceted appearance. When new, flat spots or points could increase impact pressure to improve the rate at which things got crushed in the mill, but I suspect they just naturally develop when the stuff you are crushing is partially harder than the shot.
Things to look for are asymmetric angles and numbers of facets and variations in shape and concavity/convexity from face to face, typically if something is made to be polygonal it will be regular, uniform, symmetric to a greater degree.
I don’t think ingots have ever had facets…

This ball from an old mine is 2.5” ~6.4 cm across:

19th July 2007, 04:38 PM	#2
Jeff Pringle Member Join Date: Nov 2005 Posts: 189	The grinding media used in ball mills can have a faceted appearance. When new, flat spots or points could increase impact pressure to improve the rate at which things got crushed in the mill, but I suspect they just naturally develop when the stuff you are crushing is partially harder than the shot. Things to look for are asymmetric angles and numbers of facets and variations in shape and concavity/convexity from face to face, typically if something is made to be polygonal it will be regular, uniform, symmetric to a greater degree. I don’t think ingots have ever had facets… This ball from an old mine is 2.5” ~6.4 cm across: Attached Images

19th July 2007, 02:39 PM	#1
Mark Member Join Date: Dec 2004 Posts: 987	Ric, Are ingots (wootz or not) polygonal like this, at least sometimes? I recall seeing a couple facetted ones on Artzi's table at the Timonium show a few years back. Such a polygon would not, I think, work very well as a mill ball as it would have a reduced area of contact with the ore, and would not roll around as well. Whatever it is, I expect that the shape allows them to be packed more tightly, and/or stacked more stably.