Cross-slide

For the calibration of the electronic camera in the field on the job, the diode was mounted on a cross slide which was attached to the abutment. So it was possible to move the diode on defined values before and after the brake tests to determine the calibration functions Ky and Kx of (1) (Fig. 5). As computer unit to register the signals from the electronic camera we have used an HP 200/300. With this system we obtained a measurement frequency of 40Hz. So we were within the boundary conditions. 

Figure 5 Cross slide to calibration the electronic camera...

The saddle rests on top of the bed and is guided by two guideways which, for stability, are the two furthest apart. Accurate movement is thus maintained relative to the centre line of the spindle and tailstock for the complete length of the bed. The top surface contains the dovetail slideway into which the cross-slide is located and the cross-slide lead-screw, complete with handwheel and graduated dial. Fig. 9.5. 

Mounted in the dovetail slideway on the top surface of the saddle, the cross-slide moves at right angles to the centre line of the machine spindle. Adjustment for wear is provided by a tapered gib strip, which can be pushed further into the slide and slldeway by the screw as wear takes place. Attached to the underside of the cross-slide is the leadscrew nut through which movement is transmitted from the leadscrew. Power feed is available to the cross-slide. 

On the lathe shown, external dovetails are provided along each side of the cross-slide, for quick accurate attachment of rear-mounting accessories. 

Select the feed axis required, Le. longitudinal travel of carriage or cross-slide, by means of the apron push-pull knob (19). 

When the workpiece has been clamped, check each nut and screw to ensure it is tight. Turn the faceplate by hand and check that all bolts and clamps are clear of the bed, cross slide or toolpost. To ensure this, avoid using excessively long clamping bolts. Check for out of balance of the faceplate - a counterbalance may be required. 

Figure 9.31. Cross-slide leadscrew for taper-turnirrg attachmerrt...

The sliding block is attached to the end of the cross-slide leadscrew and is guided in a bracket which is boited to the rear face of the saddle. 

Wind in the cross-slide until the tool just touches the outside of the workpiece and move the carriage so that the tool is clear of the end of the workpiece. 

A typical surface grinder is shown in Fig. 10.1 and uses a 300 mm diameter by 25 mm wide grinding wheel. The reciprocating table and cross-slide movements are hydraulically operated, although alternative hand operation is provided. 

The gearbox, fitted on the lower side of the headstock, provides the range of feeds to the saddle and cross-slide through the feed shaft, and the screw-cutting range through the leadscrew. 

In operation, the workpiece is held in the lathe chuck while the knurling tool is held in the toolpost on the cross-slide. 

The cross-slide is positioned so that the knurls are above the centre of the workpiece where they are adjusted to contact the workpiece surface using the adjusting screw. Slender work may have to be supported using a centre in the tailstock. 

Turning the angle is done by winding the top slide handle by hand. The tool will feed at the angle to which the top slide is set. After the first cut, the tool is returned to its starting position by rewinding the top slide. The feed for the second cut is achieved by moving the cross-slide. 

Figure 9.34 Cross-slide leadscrew for taperturning attachment...

Wind the cross-slide to give a small cut of 0.05mm. 

When the end of the workpiece is reached, unwind the cross-slide to remove the tool from the work and disengage the split nut. This is done in one movement. At all times during screw-cutting, one hand should be resting on the cross-slide handwheel, the other on the split-nut lever. 

Rewind the cross-slide back to the original graduation and put on a further cut. 

The table movement (x axis) is manual via the handwheel, or hydraulic for automatic reciprocation. The saddle cross-slide movement (y axis) and wheel downfeed (z axis) are controlled by digital AC servo motors. Table reversal is set by adjustable table dogs and proximity switches in the saddle. 

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