The carriage of the 6500 series is made up of six assemblies: the saddle, the apron, the friction clutch, the threading dial, the compound rest assembly, and the tool post.

THE APRON is mounted under the front of the saddle and contains the longitudinal hand feed mechanism, the power feed mechanism and the half-nut mechanism.

The handwheel on the front of the apron moves the carriage longitudinally by means of gears and a pinion engaging a rack on the bed.

The power feed selector lever is located in the center of the apron and can be located in three positions:

Up for power longitudinal feed. Down for power cross feed and center for threading.

THE FRICTION CLUTCH prevents overloading the power feed mechanism and is engaged by lifting the clutch lever (located below the power feed selector lever) and disengaged by pushing it down. Tension on the clutch is provided by a spring washer and is adjusted at the factory to feed the carriage longitudinally with a thrust of 800 pounds. The thrust can be increased or decreased by tightening or loosening the inner of the two nuts at the center of the clutch lever, being careful to tighten the locking nut against the inner nut after the adjustment has been made.

The half-nut lever is located at the right side of the apron and engages the half-nuts with the leadscrew for longitudinal motion in thread cutting. The half-nuts can be engaged only when the power feed lever is in the threading position, and the power feed selector lever can be moved from threading position only when the half-nut is disengaged.

Power is transmitted from the quick-change gearbox to the apron thru the spline in the leadscrew when the power feed mechanism is used. To minimize wear and thereby retain their accuracy, the half-nuts and leadscrew should be used only for thread cutting.

Apply a few drops of machine oil daily to the oiler in the handwheel bracket and to the oiler in the end of the shaft above it.

Maintain the level of oil in the apron to the gage mark thru the oil cup at the right side of the apron.

THE THREADING DIAL is located on the right end of the saddle and indicates the proper position at which to engage the half-nut lever during threading operations so that the tool will enter the same groove for each cut. When cutting even-numbered threads, the half-nuts may be engaged at any mark on the threading dial. When cutting odd-numbered threads (7, 11, 13, etc., per inch), the half-nuts may be engaged at either the 1 or the 2 mark. When cutting half-numbered threads (4-1/2, 11-1/2, etc., per inch), the half-nuts must be engaged at the same point on the dial for each cut.

THE SADDLE moves longitudinally on a V-way and a flat way and is held down to the bed by gibs which bear on the underside of the front and back ways. The two front gibs, one under each end of the saddle wings, are machined to bear ‘on the underside of the front V. way and are drawn up tightly by hexagon cap screws.

The back gib is adjustable by means of two Nylok socket set screws. This gib should be set tightly enough to give a firm sliding fit between the carriage and the bed making certain that the pressure is equalized to avoid any tipping or lifting action.

Felt wipers are furnished at both ends of the saddle for both front and back ways. The saddle is locked to the bed when desired by the lock screw on the right front saddle wing. The top flat surfaces on the saddle are precision ground for mounting gages, indicators, etc.

The compound rest base moves across the top of the saddle on dovetailed ways to form the cross-slide. The cross-slide moves transversely on top of the saddle guided by dovetail ways. The slide is equipped with a gib which is adjusted by means of set screws along the ‘side of the slide. After adjusting the gib, test the cross-slide for feel — there should be a slight drag but no bind. Excessive drag does not improve machine performance.

The position of the cross-slide is adjusted by means of an Acme thread screw and dial. A micrometer collar on the dial is graduated in thousandths of an inch and may be rotated to any position desired for zero start. The dial can be adjusted to remove end play as follows: