Combidex Catalog - National

Thread Inserts & Toolholder Rotation Feed Direction Helix Method Drawing No.Right Hand EX RH Anticlockwise Towards chuck Regular 1External EX LH Clockwise From chuck Reversed 2Right Hand IN RH Anticlockwise Towards chuck Regular 3Internal IN LH Clockwise From chuck Reversed 4Left Hand EX LH Clockwise Towards chuck Regular 5External EX RH Anticlockwise From chuck Reversed 6Left Hand IN LH Clockwise Towards chuck Regular 7Internal IN RH Anticlockwise From chuck Reversed 8Radial InfeedFlank Infeed (modified)Alternate Flank Infeed1-3˚Radial infeed is the simplest andquickest method.The feed is perpendicular to theturning axis, and both flanks of theinsert perform the cutting operation.Radial infeed is recommended in 3 cases:• when the pitch is smaller than 16 tpi• for material with short chips• for work with hardened materialFlank infeed is recommended in thefollowing cases:• when the thread pitch is greater than16 tpi., using the radial method, theeffective cutting edge length is toolarge, resulting in chatter.• for TRAPEZ and ACME. The radialmethod result in three cutting edges,making chip flow very difficult.Use of the alternate flank method isrecommended especially in largepitches and for materials withlong cihps.This method dividesthe load equally on both flanks,resulting in equal wear alongthe cutting edges. Alternate flankinfeedrequires more complicatedprogramming, and is not availableon all lathes.External RH ThreadExternal LH Thread1. *2.5. *6.Internal RH Thread3.*4.Internal LH Thread7.*8.*Change anvil to negative anvil. 3°N maximum56