Product Name:Lapidary Diamond Drill Bits, Gem Drilling Tools, Drilling Rocks for Jewelry. Hole Diameter:67mm, Internal Diameter:65mm, Shank Diameter:10mm. Rim Thickness:0.7mm, Total Length:55mm, Drilling depth:20mm, Quantity:1 Piece. It has held up extremely well and drilling just about any kind of rock, from the very soft Petoskey Stone fossils to hard jasper and agate of precious materials Especially suitable for use on hard lapidary materials like agate, jasper, petrified wood and geodes. The super-thin Electroplated diamond drill bits are one of the finest drill bit manufactured for Hobby, Lapidary, Glass applications. 67mm Lapidary Ultra-thin Diamond Coated Drill Bit Hole Saw 0.7-0.8 mm Rim Save Materials for Jasper Model: Diamond Hole Saw Drill Bit Type: Hole Cutter Quantity:Only 1 Piece Specifications: External Diameter:67mm Shank Diameter:10mm Rim Thickness:0.7mm-0.8mm Total Length:55mm Drilling depth:20mm Product Description 1.This diamond drill bit will perform well on any kind of rock. 2.Apply to drilling the glass of watch, optical glass and super-thin glass; 3.Used in ceramics and glass (architecture glass, automobile glass, LCD glass, quartz glass, ultra-thin glass, etc.) widely. 4.Water or coolant must always be used to cool and lubricate the tip. Product performance and advantages: Hole drilling high precision: neat, smooth, no broken edge. High drilling efficiency: Sharp, improve the drilling speed, Drill a Holes In Seconds Quick Tips 1.Please add water for coolant and drill slowly 2.Start drill at 45 Degree to surface and align to 90 Degree as hole forms 3.Never use drills while machine is in hammer action. 4.Holes Require No Futher Work As Cutting Is Clean 5.Just fill with ordinary electric drill or rotary tool, Works better with a electric drill ( Excluding in this item ) We Can List Any Size & Amount Of This Product: Hole Diameter from 3mm - 100mm