(Properly used, cleaned and maintained this chuck still has decades of service left in it. Jacobs No.3A Chuck. Jacobs MT3 Arbor. 4) A used but very serviceable Jacobs JT3 / MT3 Arbor is supplied, as shown by Photos #10, #11 & #12, with the clean JT3 taper by Photo #11 and the centre-spots on the Tang and JT3 Taper end by Photos #12 & #13.
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