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
I have 4 sets available for sale. $70 each plus $5 shipping inside US. Zelle/Venmo/etc.
It works with a AA battery and keeps rotating once you press the button.
PM me for more detail. Thank you