Southbend SB1053 owner manual Power Feed, Example 2 Spindle Speed of 1250 RPM

For Machines Mfg. Since 3/11 O P E R A T I O N 16-Speed Gearhead Lathe

4.Move the spindle speed lever so that the indicator points to the letter "A". This will select the spindle speed of 40 RPM in the top row of the chart.

Example 2: Spindle Speed of 1250 RPM

1.Make sure the spindle is completely stopped and the spindle ON/OFF lever is in the OFF (middle) position.

2.Turn the motor switch to the HIGH (right) position. This will make the speeds in the bottom row of the spindle speed chart available

3.Move the spindle range lever so that the indicator points to the lower line (see Figure 76). This will make the last four or higher speeds in the bottom row available.

Spindle Speed
Lever at “C”						Spindle Range
(1250 RPM)
	C					Lever at the
						High Range
	B
	A
	D
40	60	100	165	245	375	625 1000
80	120	200	330	490	750	1250 2000
A	B	C	D	A	B	C D

Figure 76. Setting the spindle speed at 1250 RPM.

4.Move the spindle speed lever so that the indicator points to the letter "C". This will select the spindle speed of 1250 RPM in the bottom row of the chart.

Power Feed

Both the carriage and cross slide have power feed capability when the carriage is engaged with the feed rod. The rate that these components move (feed rate) is controlled by how the levers are positioned on the headstock and quick-change gearbox, and the end gear arrangement.

Feed rate and spindle speed must be considered together. Keep in mind that the feed rate is expressed in the amount of travel per revolution of the spindle. The sources you use to determine the optimum spindle speed for an operation will also provide the optimal feed rate to use with that spindle speed.

Often, the experienced machinist will use the feeds and speeds given in their reference charts or web calculators as a starting point, then make minor adjustments to the feed rate (and sometimes spindle speed) to achieve the best results.

The carriage can alternatively be driven by the leadscrew for threading operations. However, this section only covers the use of the power feed option for the carriage and cross slide components for non-threading operations. To learn how to power the carriage for threading operations, refer to Threading on Page 58.

To avoid damaging the machine, NEVER attempt to engage carriage with leadscrew and feed rod at the same time!

Never change spindle speeds while spindle is moving! Severe machine damage will occur.

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