1-3. When using the "thread
dial" in the cutting of a thread on a lathe it is
NOT proper to close the split nut at:
(a) any
un-numbered line on the dial for a 5-1/4 per inch thread
(b)
any odd-numbered line on the dial for a 10-1/2 per inch thread.
(c) any line on the dial for a 6 per inch thread
(d)
any numbered line on the dial for a 7 per inch thread.