Tap Fractional Drill Bit Number Drill Bit
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#12-24 11/64" 16
1/4"-20 13/64" 7
1/4"-28 7/32" 3
5/16"-18 17/64" -
What size drill bit do you use for a 1/4-20 tap?
For a 1/4-20 bolt, the optimal drill bit size is #7 or 13/64th.
What drill is used to tap a 1/4-20 hole?
To Tap This Size Screw Or Bolt: Use This Drill Bit: (Closest Fractional:)
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1/4-20 NC #7 13/64"
14-24 NS #7 -
6mm-1.00mm 5.2mm -
1/4-24 NS #4 -
How is NPT measured?
NPT fittings are slightly tapered so the “nominal” diameter is the diameter in the middle of the threaded portion, as measured by the top (crest) of the threads.Jun 13, 2018
What Tap do I need for 1/4 NPT?
Tap Size Drill Size Tap and Drill Set
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1/8" NPT Tap "R" Drill Bit 1/8" NPT Tap and Drill Set
1/4" NPT Tap 7/16" Drill Bit 1/4" NPT Tap and Drill Set
3/8" NPT Tap 37/64" Drill Bit 3/8" NPT Tap and Drill Set
1/2" NPT Tap 23/32" Drill Bit 1/2" NPT Tap and Drill Set