Descripton:<br> 3pcs HSS Nitrogen Coated Spiral Grooved Step Drill Bit Set 4-12mm\/4-20mm\/4-32mm<br>  <br> Specification:<br> Color : Black (as picture shown)<br> Material : High Speed Steel<br> Surface : Nitrogen treatment (increasing the hardness and abrasion resistance)<br> Shank:Triangle round handle<br> Scop : Thin iron plate，aluminum，insulation panels，PVC panels 4mm thickness within the timber.<br> Type:<br> 4-32mm: 15 Steps (4mm，6mm，8mm，10mm，12mm，14mm，16mm，18mm，20mm，22mm，24mm，26mm，28mm，30mm，32mm)， Shank:25 x 10mm<br> 4-20mm: 9 Steps (4mm，6mm，8mm，10mm，12mm，14mm，16mm，18mm，20mm)， Shank:20 x 8mm<br> 4-12mm: 5 Steps (4mm，6mm，8mm，10mm，12mm)， Shank:20 x 6mm Quantity: 3 pcs<br>          Features:     No need for a pilot hole.     Titanium coated to reduce friction and run cooler.     Large bit has 3 sided shank.     Automatically deburr holes as you drill.     High speed steel，durable.     Widely used to cut holes in a variety of material like steel， wood， thin iron， aluminum alloy， insulation boards， PVC sheet，ect..     <br> Package included:<br> 1 x 4-12mm Spiral Grooved Drill<br> 1 x 4-20mm Spiral Grooved Drill<br> 1 x 4-32mm Spiral Grooved Drill<br>  <br> More Details: