On 3/18/2013 12:32 PM, Tom Dacon wrote:
I used to have a nice little 4-inch plastic caliper, with both decimal
and fractional rings on the dial.

Not plastic but what you are looking for...

http://www.ptreeusa.com/layout_products.htm#1241

or

http://www.woodcraft.com/product/200...l-caliper.aspx

or

http://woodworker.com/6-fractional-d...su-149-426.asp

http://woodworker.com/5-slide-caliper-mssu-946-638.asp (my favorite)

http://www.harborfreight.com/6-inch-...per-92437.html