I'm tired of paying ridiculously overpriced radial drill taps, so I talked to a friend in Japan who works at a factory that machines drills and drill taps, to have an original radial tap made. He first said that it was very difficult to machine ball threads, but after several rounds of sampling...
The shank diameter was too large and didn't fit my Cue Smith drill chuck. I believe this type of coolant hole can be used with a coolant-delivery spindle typically used in metal machining, with a water-based coolant.
I have two gun drills for sale. They are both new, unused. They just didn't fit in my Cue Smith drill chuck.
0.775" and 0.650" coated carbide tip with 2 coolant holes.
17" flute length, 0.7" shank diameter.
$85 each or $150 for both.
$5 shipping to 48 states.
Paypal/Venmo/Zelle