94) Which lap material is inexpensive and can be expanded if worn out?

95) Which type of abrasive material is externally hard and used in lapping for heavy stock removal?

96) Which abrasive is used for lapping dies and gauges?

97) Which is the hardest of all abrasive material and used for lapping tungsten carbide?

98) What is the abrasive used for lapping accurately finishing very small holes?