Designed for mounting bowls by expanding into a recess or clamping onto a spigot.
The sizes indicated on the drawing are when the jaws form a perfect circle, which is achieved when the jaws are 2mm apart. VM120 and VM150 chucks provide approx 48mm of expansion beyond these specified sizes.
Adam (Submitted on Mar 14th 2016)
Great jaws for 12"-`17" diameter, I do bowl coring and these jaws help me keep the blank well sited while coring. You Can't go wrong with Vicmarc and customer service is the best at WoodworkersEmporium, if you have a question ask for Brandon.