“The use of the 1/4 x 6" did not perform well and did not appear to have the sintered diamonds as in the other products. The bit did not bore much and then must have caught a portion of a core and cracked the bit tip-rendered unusable. We had ordered 2 bits, the second one also did not perform well and only performed ~1/4" depth of coring. The stone is jade where we are well aware of the mhos hardness, and used other bore bits successfully. Marble and limestone are softer and potentially more appropriate for these bits”
