INTEGRATED TOOLING SOLUTION'S TAP DRILL CHART

For Roll Form Tapping of Aluminum Die Casting parts in common Automotive thread sizes.
This chart will help you determine the approximate hole size after tapping and selection of the best tap drill size.

1. Select tap diameter and pitch.
2. Tap drill size shown in metric and decimal, and thread percentage.
3. Recommended tap "D" or "H" limit to use.
4. Minor diameter tolerance.
    Note: Metric sizes are for 6H minor diameters and English sizes are for 2B minor diameters.
5. Approximate minor diameter after tapping.

Note: The hole size after tapping is an estimated number. Factors that affect this are part design, machine capability, tapping speed, and coolant lubricity. This will also apply to Roll Form Tapping of other ductile materials.

Tap Drill Chart Key:

Out of tolerance for minor diameter. Too high thread %. Almost no tap life.

Tap drill range that will hold minor diameter after tapping.

Best tapping range for holding minor diameter after tapping.

Out of tolerance for minor diameter. Best tap life if minor diameter is not required to be held after tapping.

Select Tap Size:
6-32 NC
8-32 NC
10-24 NC
10-32 NF

1/4 20 NC
1/4 28 NF
5/16 18 NC
5/16 24 NF
3/8 16 NC
3/8 24 NF
7/16 14 NC
7/16 20 NF
1/2 13 NC
1/2 20 NF
9/16 12 NC
9/16 18 NF
5/8 11 NC
5/8 18 NF
3/4 10 NC
3/4 16 NF

M3.5 X 0.60
M4 X 0.70
M5 X 0.80
M6 X 1.0
M8 X 1.0
M8 X 1.25
M10 X 1.25
M10 X 1.5
M12 X 1.25
M12 X 1.75
M14 X 1.25
M14 X 1.5
M16 X 1.5
M16 X 2.0
M18 X 1.5
M20 X 1.5
M20 X 2.5
M22 X 1.5

2006 Integrated Tooling Solutions, Inc.