ZELX AL PO 1/4-20 H3 Spiral Point 3 Flute Plug Tap Manufacture YMW Mfg Part Number 386207 Size (Inch) Thread Limit H3 Number of Flutes 3 Chamfered Plug Lead 3 to 5 Finish/Coating Black Oxide Material Vanadium High Speed Steel Oversize (Yes/No) No Length of Thread .748 Overall Length (Inch) 3.150 Thread Standard UNC Tapping Materials: Wrought Aluminum Alloys Copper Zinc Alloys Tapping Aluminum: 95-125 SFM Tapping Copper: 35-80 SFM, Tapping Brass: 50-70 SFM