Southbend SB10146PF Even TPI Not Divisible By, Odd Numbered TPI, ⁄2 Fractional TPI, 27⁄8 TPI

Turn-Nado®Gearhead Lathes O P E R A T I O N For Machines Mfg. Since 3/11

Even TPI Not Divisible By 4

For threading a TPI that is even but not divisible by 4, use any of the non-numbered lines on the thread dial (see Figure 83).

TPI

2,6,10,14,	Non-
18,22,26,	Numbered
30,54	Position

Figure 83. Marks are selected on the dial for threading

even TPI not divisible by 4.

Odd Numbered TPI

For odd numbered TPI, use any of the numbered lines on the thread dial (see Figure 84).

TPI
3,5,7,9,	Numbered
11,13,15,	Position
19,23,27	1,2,3,4

Figure 84. Numbers are selected on the dial for

threading odd numbered TPI.

1⁄2 Fractional TPI

Use any opposing number pairs—2/4 or 1/3 on the thread dial for 1⁄2 fractional TPI (see Figure 85). For example, to cut a 31⁄2 thread, select 1 or 3 on the dial.

1⁄4 or 3⁄4 Fractional TPI

For TPI that have a 1⁄4 or 3⁄4 fraction, use position 1 on the thread dial (see Figure 86).

TPI

2¼,2¾,	Position
3¼,3¾	1 Only

Figure 86. Position for 1⁄4 or 3⁄4 fractional TPI.

27⁄8 TPI

The thread dial is not used for 2⁜7⁄8 or metric threading, or diametral and modular pitches (see Figure 87). The half nut must stay engaged with the leadscrew throughout the entire threading operation.

27∕8	Same as	Thread Dial
	Metric
		Not Used
	Threads

Figure 87. Half nut stays engaged for 27⁄8 TPI.

TPI

2½,3½,4½,

7½,11½,13½

Position 1,3 or 2,4

Figure 85. Opposing number group are selected on

dial for cutting 1⁄2 thread TPI.

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