Transcription of Hole Sizes for Cut Tapping - STANLEY® Engineered Fastening
1 - 1 Sizes for Cut TappingThese charts are supplied as a recommendation only. Actual Sizes may vary depending on application and the material being tapped. Other thread and hole Sizes are available upon request or on our website drill size calculator. For aluminum or other soft materials a hole minor diameter on the low side of the suggested range isrecommended. For harder materials, a hole minor diameter near the high end of the suggested range is recommended. Spiralock threaded holes require the use a larger minor diameter than conventional fractional Thread SizeHole Minor Diameter Min. (in) hole Minor Diameter Max. (in)Suggested Drill size *0 #551 #521 #522 #482 #443 #434 #414 #405 #356 #336 8 #288 #2610 #2110 #1912 #1312 #121/4 #41/4 #25/16 mm5/8 mm1 mmMetric Thread SizeHole Minor Diameter Min.
2 (mm) hole Minor Diameter Max. (mm)Suggested Drill size * x # x # x # x # x x # x # x x # x x x x mmM10 x x x x mmM12 x x x mmM14 x x mmM16 x x mmM18 x x mmM20 x x mmM22 x mmM24 x *Drill size callouts were determined to best fit the hole minordiameter range Cutting tapImage Balax, Inc. Used with 2 Sizes for Cold Form TappingThese charts are supplied as a recommendation only. Finding the correct drill size for a Spiralock tap may be a Cut and Try process: Not all drills are alike - to get good results, verify the actual hole size being produced by the drill Thin wall parts may expand during Tapping and produce oversize after-tap minor diametersAfter Tapping , the hole size should fall within the Spiralock recommended minor diameter range for cut threads.
3 If the final minor diameter is below the range for a cut thread, use a larger drill. Do the opposite for afinal minor diameter that is larger than the recommended range for cut Thread SizeMinor Dia. Min. (in)Minor Dia. Max. (in)0 20 28 Thread SizeMinor Dia. Min. (mm)Minor Dia. Max. (mm) x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x Balax, Inc. Used with tap with oil groovesNo Chips
