Discussion on "Cold metal working" at the Coventry Section of the Institution

MR. DRANE : How do you ensure that the shank of the bolt shall be concentric with the head? Also, to what degree of accuracy can the diameter be guaranteed? I assume they are controlled as the diameter of the shank must have some bearing on the ultimate thread produced. Have you had any experience with thread rolling multi starts? I think you have only spoken about Whitworth threads. What is the nearest to a square thread which you can roll cold? Will you tell us something about the life of the dies. I should also like to know about the adjustment of the dies.