DIAMOND DIES FOR DRAWING OF COPPER WIRE 23 



tained from different sources the variations narrow after one or two recuts. 

 This is to be expected when standardized recutting practises are followed. 



Bell Angle 



The bell angle should permit ready ingress of the compound solution to 

 wash out those materials (dust, slivers, sludge, dirt, etc.) which tend to 

 accumulate here and have an abrasive action when pulled through the die 



Fig. 2 — Defective diamond die mounting due to poor metal flow 



by the wire. The bell angle is highly polished to minimize the packing of 

 the noted materials. This polish can be more easily achieved in a smooth 

 tapering angle than in one of a wide flare. 



Approach Angle 



At high drawing speeds, appreciable wire whip and vibration are present. 

 Also, the higher centrifugal forces tend to "throw out" the wire in relation 

 to the normal axis of the die. An approach angle not too wide in relation 



