These are the Charnwood Stepped Jaws for Nexus 3 Chuck.
Set of 4 optional jaws for our Nexus 3 geared scroll chuck. The Stepped jaws have a serrated edge both internally and externally. They give great flexibility by combining standard sized jaws and pin jaws. Jaws project 24mm from base plate.
Step 1 Expands from 19mm to 46mm
Step 2 Expands from 38mm to 65mm
Contracts from 30mm to 3mm