HeliCoil Oversize Inserts - When to Use HeliCoil Oversize Inserts are recommended for correcting tapping errors that cause HeliCoil assemblies to gauge oversize. Conditions of slight taper or bell-mouth in screw thread insert tapped holes are easily corrected. However, when the oversize condition of the hole is beyond the corrective range of HeliCoil Oversize Inserts, HeliCoil Twinserts should be used
