MTDCNC talks Gun-drilling with the experts at Guhring

[@PeteMetcalf]

Can you use a (single edge) gundrill on a CNC lathe? for example 17.5mm diameter drilling say 190mm deep in 304 stainless steel? I have a project at work and we are currently using a standard twist drill for the first 100mm then switching to (what I know as) a spade drill with chnageable cutting head

[@PeteMetcalf]

Also, whats the accuracy rate? as after drilling we are then boring to 17.8mm, can you buy drills at that size and will they hold tolerance of say + - 0.1?

[@1008chaz]

You can use them on a lathe but you need really good coolant pressure & you can't use the really long gundrills without support bushings so your use case really depends on your total depth. I use botek drills on a boring mill style gundrilling machine and the center line deviation is about .2-.3mm past 500mm deep (the diameter stays pretty much bang on no matter how deep you go)