b'Letter to the EditorSUGARCOATING IT design the correct features so theFrom an engineering standpoint, tool would function properly for theI will disagree with Mr. Friedli about The following was written in re- application and material to be cut.only coating for two diameters of sponse to Alan Richters Lead AngleI could not wait to get my copy offlute length. The cost of the coat-column in the March issue about theCTE to find out what was new toing material is insignificant com-amount of coating for a drill. our business and what the compe- pared with the labor cost to mask tition was up to. It served as part ofoff the tool for only two diameters Im a longtime reader of CTE.my training. In time, I became headof coating length. Yes, he is correct I was hired into the business byof design and engineering and Mo- about the point taking most of the Frank Hofbauer, the late founderhawks cutting tool expert. Enoughabuse from heat generated at the and president of the old Mohawkabout me. chip interface along the cutting lip. Tools Inc., Montpelier, Ohio, in 1967ItakemyhatofftoMr.PaulFlank and crater wear generation as a draftsman. Frank came up withFriedli to still have an interest inare dependent on many different the subland drill for drilling andour business at his age of 91. Imfactors.Axial rake (helix), clearance chamfering shells and bombs forsure he has won the title as oldest(lip relief), speed and feed are just World War II, along with many otherreader, and congratulations. I woulda few that must be correct for the innovative cutting tools. I learnedbe curious to know how long hematerial and hardness being cut. If the craft from the best. During myhas been reading CTE. I have beenyou are drilling three diameters of apprenticeship, I was taught everyreading CTE since 1967. I had col- depth or less, then the coating on operation to produce a cutting toollected all of the copies until aboutthe margins and flute face becomes and every engineering function to10 years ago. less important.However, drilling deeper than three diameters of depth is consid-ered deep-hole drilling, and most operators do not retract the drill to extract chips. Chip congestion in the flutes is the leading cause of drill failure. A tapered web general-purpose drill is not appropriate for deep-hole drilling, but parallel web parabolic flute-form drills are better suited for deep-hole drilling. If the drill has a coating on the margins and flute face for the entire length, CTE E-News puts your ad in a winning position then it gives self-lubricating and wear resistance properties so the chips can flow easier up the flutes, Youll score the TOP SPOT with CTEscarrying heat away from the pointLEADERBOARD position andwhere it is created. Heat is any cut-reach our E-News subscribersrst! ting tools worst enemy. Coatings are only an enhancement and not a substitute for proper design and ap-plication for the material and hard-ness being cut. Drills are the most abused cutting Why fall behind when you can take the lead?tool and remove more material than all of the others in the magazine.Find out more at ctemag.com/advertise Keep up the great work that you do.CTELynn Fifer 10 MAY 2020Letter.indd 26 4/17/20 2:08 PM'