b'some fastenersHi-Loks, for ex- with Win that most cutting toolstions and what theyre trying to ac-amplecall for a slight radius atused to make fastener holes arecomplish. We also have the ability the transition point where a drillspecials. to test these solutions in our own meets a countersink. This createsEasily 90% of our stuff is appli- lab if the customer so desires, using a relief that reduces stress on acation-specific, which is why its sotheir material and fasteners. This al-fastener, hopefully eliminating theimportant to develop relationshipslows us to fine-tune the tool geom-possibility of its head popping offwith the engineers at these com- etry and coatings and develop the in flight. panies, Thurnau said. That way,best possible solution for their re-This is less of a concern on com- we can understand their specifica- quirements.CTEposite structures as these provide a little more give than with a metal-on-metalconnection,Rozema said. In either instance, however, the radius also helps assure that the head will sit perfectly flush with the fuselage surface, something thats crucial to its laminar flow.Dan Thurnau, applications engi-neer for Amamco Tool & Supply, works with aerospace customers around Wichita, Kansas. He agrees Amamco Tool & Supplyctemag.com/cteguide.com35Countersinking.indd 35 4/16/20 4:59 PM'