Taper taps have eight to ten threads chamfered to start and cut threads easily, in a through hole, which is open at the bottom.
Plug taps have three to five threads chamfered, to cut threads in a through hole, or to start threads in a blind hole, closed at the bottom.
Tap Drills are smaller in diameter than the screw shaft to leave enough metal to cut threads.
Clearance Drills are large enough to allow the body of the bolt to pass through the hole.
Tap Drill: for 6-48 thread, use No. Drill-31
Clearance Drill: for 6-48 thread, use No. Drill-25
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drill bit, HSS, Number 25, .1495" diameter, clearance drill No. 6 bolt or screw
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drill bit, HSS, Number 31, .1200" diameter, tap drill 6-48 thread
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Tap, high speed steel, 6-48 thread, bottom tap
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Tap, high speed steel, 6-48 thread, plug tap
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Tap, high speed steel, 6-48 thread, taper tap
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Tap handle, accepts #0 to #8 diameter taps
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