"F. George McDuffee" wrote in message
...
On Sat, 2 Feb 2013 08:39:18 -0600, "Paul K. Dickman"
wrote:

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Wouldn't a tank head work the same?
http://www.cmforming.com/tankheads-and-accessories.htm
snip

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Thanks for the link.

Yes, but the cost is higher than a used disk (I think)

That would depend on circumstances I suspect. We used to play softball in
the desert at an Easter picnic every year. We used old discs as bases.