Thread Rolling Using Two OR Three Roller Type Dies
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Thread Rolling Using Two OR Three Roller Type Dies
Thread Rolling Using Two OR Three Roller Type Dies - The second method of thread rolling uses two or three roller type dies. Fig illustrates the three roll method, two variations being used. In one the rolls are retracted while the blank is placed in position; then they are moved inward while rotating to form the thread.
| A - Work | B - 3 Cylindrical Dies in Rollong Position | C - Cylindrical Dies Retracted Position |
Three Die Types used in Cylindrical Die Thread Rolling Machines
In a more common procedure, used on turret lathes and screw machines, the three rolls are contained in a self opening die head, similar to the conventional type used for cutting external threads.
The die head is fed on to the blank longitudinally and forms the thread progressively as the blank rotates. With this procedure, as in the case of cut threads, the innermost 1 1/2 to 2 threads are not formed to full depth because of the progressive action of the rollers.
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