Roll Tap Drill Chart

Roll Tap Drill Chart. In addition to this there is a table with recommended drill sizes for npt threads. (mm) — (0/0 of thread desired x mm pitch) 147.06 (65 x 1.25) = 7.45 mm dia.

ToolScoot Cart for HSK63A tooling Huot Manufacturing from www.huot.com

Roll taps can be easily identified by their concentric threads going around the cutting tool. Íthe control of the hole size before roll tapping must be held to a closer tolerance than that of cutting taps. 50% thread for steel, stainless & iron 75% thread for aluminum, brass & plastics.