2

Looks like sap/resin that trees produce when they are damaged (e.g. by grown-in branches). It indeed hardens over time and can be trapped within the growing tree.


2

Friction drives allow the tail center to adjust the tension and allow or constrain spinning of the drive in reference to the blank. The drive is actually the outer rim, not the inner point. The inner point is more for registering the blank and within reason, any tension is probably appropriate as long as the tail stock provides enough tension to turn the ...


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