High-Carbon Steel Fractional Bottoming TapIdeal for routine maintenance, repair work and for re-threading where high accuracy and tolerance thread is not critical. Straight flutes are ground to provide rapid chip removal for efficient threading. Designed for hand threading work in a variety of materials. Taps produce a class 2B thread. Applicable Materials: Most Metals; Cutting Direction: Right; End Shape: Chamfer - 1 1/2 Threads; Material: High Carbon Steel; Number of Flutes: 4; Style: Bottoming; Thread Size: 5/16 in; Thread Standard: NC; Threads Per Inch: 18; Weight: 0.03 lb.