Be Aware of Burrs with Roll Tapping

The nature of rollform form tapping inherently will cause a bur.  This is due to the fact the rollform tapping forms and displaces material v. cutting out material with cut tapping.  While rollform tapping is a stronger thread than a cut thread, the burs that are produced need to be addressed.  Generally this is done but countersinking the hole so that the burs will not protrude past the top and bottom face of the material.

Another issue that comes up when rollform tapping with In-die tapping is making a clearance hole in the die for the burs from the rollform tapping operation.  If there is not a clearance hole the likely result will be the bur being pushed back into the bottom of the tapped hole.  This will result in having the go gage work to the bottom of the tapped hole and stopping at the last thread. By providing clearance in the die this issue is easily resolved.