Al,
I think yer talking bout a holdfast...
apperently there are different types,
i used the hammer in type, built like the number 7.. but here at this link is another one of a different design,,,
http://www.rockler.com/ecom7/product...ilter=holdfast
that link shows a holdfast forsale, not the tap in type, looks like the working end of a bar clamp...
$24.00 each
if your wood vise has a retractable dog on the outer jaw, check out the bench dogs and pups ... they dont crush your carving as bad....