31. The wall thickness is maintained by controlling the gap between the roller and the mandrel . 32. The mandrel does not move forward and there is no collapsable mandrel in the process. 33. The mandrel does not move forward and there is no collapsable mandrel in the process. 34. For hard materials or high volume use, the mandrel is usually made of metal. 35. Furthermore, because of the mandrel they are more prone to failure from corrosion and vibration. 36. One way is to use a hollow billet and then use a fixed or floating mandrel . 37. Mandrel is extracted, leaving a final geometric shape but can be left in some cases.38. Writer Bob Baker on the recent DVD release also expressed his disappointment with the Mandrel design. 39. It is also less commonly used for non-sparking tools and mandrels for metal spinning. 40. For some tube bending processing, a mandrel is placed inside the tube to prevent collapsing.
