25. Trouble Shooting Description of products Troubles Over-cutting of internal thread Check point Segments Prevent uneven in Prevent over Prevent welding Check cutting condition Prevent unbalance feed of tap cutting on thread on entering Hardness Shape Workpiece ●Provide bigger bored hole. ●Prevent slanting of hole. ●Provide countersinking on the hole entrance. Bored hole ●Adjust a feed. Machine Feed according to pitch. Use tap holder of floating Prevent vibrating of axis of tap. type. Prevent centering-off with Jigs, Holders work piece. ●Use tap holder of floating type. ●Reduce cutting speed. Cutting condition ●Use other cutting lubricant which prevents cold welding. ●Check the viscosity. Lubricant On process Provide oxide surface treatment. Selection Use tap with oil hole. Provide small cutting angle. ●Provide short thread length. ●Reconsider number of flules ●Reconsider length of cutting of tap. chamfer. ●Adjust chamfer relief angle. Tap Design Check the width of thread margin. ●Remove burrs on teeth after ●Provide precise re-sharpening. Care for vibration. Information re-grinding. Technical Re-grind ●Provide proper land. : Most suitable solution : Second most suitable solution Technical-75 846