Hi Joe,
I’m hoping other members will post their thoughts as well.
Calluses develop from repeated use. Nothing new there. When chip carving the pressure points where calluses form should be on the final part of the index finger before the knuckle. This area is where you press down on the knife to make the cut.
The calluses on your thumb joint should not be there. They indicate too much pressure there and not on the index finger where it should be.
Glad to know you’ve completed the Chip CArving Essentials Course! Great!!
Marty