iron ignot?

Tim Simmons · 19th July 2007, 06:48 AM

Grape shot or a lump of canister shot? It would not have to be well formed like a cannon ball?

kronckew · 19th July 2007, 06:59 AM

looks like it would work fine in an onager

Richard Furrer · 19th July 2007, 02:31 PM

Hello All,
Indeed it was Jeff who pointed the direction of the mill ball.
The few I have had chemically tesed which a friend had from India were high in chromium which places it outside the wootz realm.

Etching a window will show you if it is cast or not, but not much more.

I have a few more here which I have yet to test so I cannot comment on what ALL of them are.

Ric

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	#5
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, 06:48 AM	#1
Tim Simmons Member Join Date: Dec 2004 Location: What is still UK Posts: 5,844	Grape shot or a lump of canister shot? It would not have to be well formed like a cannon ball?

19th July 2007, 06:59 AM	#2
kronckew Member Join Date: Mar 2006 Location: Room 101, Glos. UK Posts: 4,216	looks like it would work fine in an onager

19th July 2007, 02:31 PM	#3
Richard Furrer Member Join Date: Mar 2006 Location: Sturgeon Bay, Wisconsin Posts: 163	Hello All, Indeed it was Jeff who pointed the direction of the mill ball. The few I have had chemically tesed which a friend had from India were high in chromium which places it outside the wootz realm. Etching a window will show you if it is cast or not, but not much more. I have a few more here which I have yet to test so I cannot comment on what ALL of them are. Ric

19th July 2007, 02:39 PM	#4
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.