2010 Full-Line Drill Catalog - Desanto

The drilling processA brief introductionto the subject of deep hole gun drillingIn the machining world, drilling depths of 10 x D and deeperare regarded as deep hole drilling operations, wherebysmaller drilling depths can naturally also be produced withgun drills. Advantage is taken of the positive side effects,as for example good surface quality, low deviation fromconcentricity and optimised alignment accuracy.High pressure cooling -has become a matter of course.In recent years, internal cooling has established itself forall drilling tools. Coolants are now living up to their nameand being supplied via coolant ducts to where they areurgently required. Considerable improvements in tool lifeand less breakages have been achieved by this measurefor twist drills, taps etc.Every conventional machine tool currently on the marketcan be supplied with high pressure internal cooling and istherefore also suitable for deep hole drilling.The share of gun drills on machining centres, lathes etc. isforever gaining more importance. The process is thereforeincreasing in popularity in the machining world.All gun drills must havesupport for the pilot hole.Gun drills must never operateat full speed withoutsupport in the machineshop.Deep hole drilling is nota closed book, but can bemastered by anybody aslong as certain conditionsare adhered to.Recommended cuttingrates for the application ofGuhring gun drills can befound on the pages for theindividual types!Typical procedure with all gun drills onconventional machine tools:approx. 200 rev./min, feed rate approx. 500 mm/min.without wood pecking.after reaching hole depth.Application advicethe use of two or more gun drills, e. g. Ø 10 x 400 mmand Ø 9.95 x 800 mm.enter the pilot hole revolving in the left hand direction.the use of gun drills with polished flutes.should be supplied with point grind 180° and coolantchamber.minimum oil content of 10 %.Deep hole drillingon conventional machine toolsDeep hole drilling machinesTechnical1. operation - pilot holeworkpieceL=1,5xD+0,03+0,012. operation - deep hole drillingDDcoolant cycleworkpieceworkpiececlampingdrilling bush holderdrilling bushspindle unitcoolant cyclefeed drivehigh pressure pumpfilterhigh pressurepumpfilterMMMM318