Now a days Gun drills can be used on new generation machining centers like HMC , VMC having high pressure through spindle coolant system , to produce deep holes
As single lip Gun drill is not self centering and due to its longer length ,needs guide at the entry by way of pilot hole
Steps are :-
1) Produce pilot hole to length 1.5 times to drill diameter , with tolerance of H8 ,
2) Enter Gun drill in pilot hole at low rpm,
3) Switch on coolant & rpm with recommended parameters ,
4) Complete drilling with proper feed ,
5) stop rpm & retrack drill up to pilot hole,
6) Make coolant stop and remove drill from hole ,
Warning :- Never rotate Gun drill in air , with out guideing.
