The literature on cutting metric threads on a Myford 7 Series lathe refers to the use of a 21 tooth change wheel which is now effectively extinct. I have prepared a table showing gear trains for all the ISO metric series threads in my copy of the Dormer Tap and Die Handbook using the readily-available…
At the very least, those seeking to run their lathe regularly at higher speeds may wish to consider this roller-bearing conversion described by Ken Willson. You may download the article HERE This article originally appeared in the Model Engineers Workshop issue 175 April 2011.
