b'The No. 1 issue I deal with is improper stock allowance.Boring Ending accurately control bore size. based Kennametal Inc., for exam-Although it may sound challeng- ple, each 1 m (0.00004") radial ad-ing, making very slight adjustmentsjustment can be made simply by challenges is getting consistentto fine boring tools can be easy.turning the adjusting ring until a hole quality. Using the Romicron fine boring sys- click is heard, said Michael Hacker, Issueswithholelocation,tem from Latrobe, Pennsylvania- senior global product manager for straightness and roundness are often byproducts of bores that were not sufficiently prepared, said Matt Tegelman, applications and product manager at BIG KAI-SER Precision Tooling Inc. in Hoff-man Estates, Illinois.He believes that rough boring is the best way to prepare a hole. A twin bore roughing tool with two cutting edges can be used to en-sure that a hole is round and prop-erly located for finishing, he said.Finish Boring BasicsA finish boring step is needed to meet tight tolerance requirements for roundness, straightness, posi-tion and surface finish. For exam-ple, Tegelman said fine boring is necessary whenever diameter tol-erances are tighter than 0.05 mm (0.002").The cutting edge of a finish bar is moved by a micrometric mecha-nism to adjust the bore diameter. When using boring heads from BIGHIT THE NUMBERSKAISER Precision Tooling, this usu-ally is done with a micrometer screw,LARGE DIAMETER DRILLING FOR but other boring heads employ dif- HIGH-CALIBER AEROSPACE PARTS. ferent mechanisms. Whatever the mechanism, he said the goal is theAchieve tight tolerances on the toughest materials with the B-Series same: to adjust the cutting diameterBTA drilling machine.Equipped with a high-performance in the finest possible increments topowertrain, the B-Series generates accurate and efficient on-center holes up to 630mm diameter on the most challenging aerospace applications. And with a swing over bed up to 2,000mm, you can confidently handle irregularly-shaped workpieces.about the authorTHE TRUSTED LEADER IN AEROSPACE DEEP HOLE DRILLING.William Leventon is a contributing writer for CTE. Contact him at 609-920-3335 or wleventon@ UNISIG.COMgmail.com.ctemag.com/cteguide.com31Boring.indd 31 6/17/21 11:04 AM'