Technical Information Illustrations of Tap Terms pitch tap crest basic crest angle of thread flank min tap major basic height of diameter thread basic major diametermax tap major base of thread diameter basic pitch diameter basic root basic minor diameter concentric margin cutting edge relief to cutting edge no relief eccentric relief heel cutting face Concentric Eccentric Relief Con-Eccentric Relief tap major diameter basic minor diameter Negative Hook 0º Hook Positive Hook Negative Rake Radial Rake Positive Rake Reprinted with permission from United States Cutting Tool Institute (USCTI). Published by Kennametal Inc. © 2014. All rights reserved. Y88 widia.com Technical Information