Troubleshooting Views: 16

An uneven chamfer (deeper on one side) has these common causes and fixes: 1) Surface not perpendicular - the hole axis is not perpendicular to the workpiece surface (angled hole, sloped surface); a standard countersink contacts one side first; fix: use an angled-hole countersink (spot facer with offset pilot) or center-drill first for alignment; 2) Tool runout - mis-clamping or spindle runout makes cutting uneven; fix: re-clamp, check collet and spindle, shorten overhang; 3) Workpiece not secure - movement during machining; fix: clamp firmly, add support; 4) Feed too fast - unstable cutting; fix: reduce feed, cut in slowly; 5) Dull tool - high cutting force pushes the tool aside; fix: re-sharpen or replace; 6) Weak machine rigidity - old or small machines deflect with large tools; fix: lower speed and feed or use a more rigid machine; 7) Sloped surfaces - always use an angled-hole countersink on slopes; a standard countersink will always cut unevenly there. Work through these points and the problem is usually solved.