Southbend SB1037 - Manual (Page 51)

For Machines Mfg. Since 7/09 EVS Toolroom Lathes
-49-
O P E R A T I O N
Using Thread Dial and Chart
Find the TPI (threads per inch) that you want
to cut in the left column (see Figure 92), then
reference the dial number to the right of it. The
dial numbers indicate when to engage the half
nut for a specific thread pitch. The thread dial
chart can also be found on the front of the thread
dial housing.
4,8,12,16,20,24,
28,32,36,40,44,
48,56,60,72 Any Position
In.
Non-
Numbered
Position
Numbered
Position
1,2,3,4
Position
1,3 or 2,4
Position
1 Only 2,6,10,14,
18,22,26,
30,54
3,5,7,9,
11,13,15,
19,23,27
2½,3½,4½,
7½,11½,13½
2¼,2¾,
3¼,3¾
2 7 ⁄ 8
1
2 3
4
Same as
Metric
Threads
Figure 92. Thread dial chart.
The thread dial is not used for metric threading
or for diametral or modular gear turning. You
must leave the half nut lever engaged from the
beginning until the threads are complete for
these types of operations.
The following examples explain how to use the
thread dial chart.
TPI 4-72 Divisible By 4
Use any line (position) on the thread dial, shown
in Figure 93, for threading TPI divisible by four.
Figure 93. Any position on the dial for threading 4-72
TPI.
4,8,12,16,20,24,
28,32,36,40,44,
48,56,60,72 Any Position
TPI 2-54 Not Divisible By 4
Use any of the non-numbered lines on the thread
dial for threading the TPI shown in Figure 94.
TPI
Figure 94. Marks are selected on the dial for threading
2-54 TPI.
Non-
Numbered
Position 2,6,10,14,
18,22,26,
30,54
TPI
Odd Numbered TPI
Use any of the numbered lines on the thread dial
for threading the TPI shown in Figure 95.
Figure 95. Numbers are selected on the dial for
threading odd numbered TPI.
Numbered
Position
1,2,3,4 3,5,7,9,
11,13,15,
19,23,27
TPI
1 ⁄
2
Fractional TPI
Use any opposing number pairs—2/4 or 1/3 on
the thread dial for
1 ⁄
2
fractional TPI (Figure 96).
For example, to cut a 3 1 ⁄
2
thread, select 1 on the
dial, then start threading, using 1 or 3 as your
reference points.
Figure 96. Opposing number group are selected on
dial for cutting 1 ⁄
2
thread TPI.
Position
1,3 or 2,4 2½,3½,4½,
7½,11½,13½
TPI