YMW 1/4-20 Roll Form Tap 2-2-1/2 Lead Manufacture YMW Mfg Part Number 388470 Size ( US ) Thread Limit H3 Number of Lobe Grooves 1 Chamfered Bottom Lead 2 to 2-1/2 Finish/Coating Nitride Material Vanadium High Speed Steel Oversize (Yes/No) No Length of Thread .748 Overall Length (Inch) 3.150 Thread Standard.