Drill Size For 1/4-20 Form Tap - This size is recommended for 1/4″. Subtract this amount from the od. Thread forming taps can be very effective. — (.0068 x % of thread. 1 divided by tpi ( threads per inch) step 2. Look in the chart's first column for. Web to establish tap drill sizes for inch size roll forming taps tap drill size = basic tap o.d. Web straight hole size for 75% thread: Web use this chart from kodiak cutting tools for reference with thread forming tap drill sizes.
Thread forming taps can be very effective. Subtract this amount from the od. Web use this chart from kodiak cutting tools for reference with thread forming tap drill sizes. 1 divided by tpi ( threads per inch) step 2. This size is recommended for 1/4″. Web straight hole size for 75% thread: Look in the chart's first column for. — (.0068 x % of thread. Web to establish tap drill sizes for inch size roll forming taps tap drill size = basic tap o.d.