Sherline Mill Ball Screw Z Axis Retrofit Kit 6800

Key Upgrade Parts

The key upgrade parts for this ball screw retrofit kit include a ball leadscrew, stepper-motor coupling, vertical milling column saddle for ball screws, and column saddle Z-axis ball nut mount.

Ball Leadscrew Specifications

• Rolled Ball Screw with BSH Nut
• 10mm Diameter, 2mm Lead
• C7 Accuracy*, P1 Preload
  *C7 accuracy has a linear tolerance of 50 micrometers / 300mm or .002″ / 12.0″.

SPECIAL NOTE: The new column saddle on the Z-axis is longer, and the headstock mounts towards the bottom of the saddle. We did this because the 45046 “column saddle Z-axis ball nut mount” would not allow the original saddle to move low enough to the top of the mill table. Additionally, the P/N 45046 reduces the overall amount of Z-axis travel. For this reason, we suggest that you upgrade to the P/N 45265 the (15″ Column Bed with electroless nickel with Teflon plating). This bed makes up for the loss of travel in the Z-axis, and it also adds increased lubricity and rust prevention due to the nickel and Teflon plating.

Ball Screw Z Axis Required Ordering Information

When ordering your new Ball Screw Retrofit Kit, you will need to supply the following information for your current machine so we can ensure you receive the correct length of the ball screw for each axis:

• Machine Model:___________________
• Table (Mill) Length: _________________
• Mill Base Length: __________________
• Mill Column Bed Length: _____________
• Does your vertical milling column base have a 1/2″ through-hole for the Y-axis Brass Cover Tube?

Regarding Retrofits

1. The charge for all ball leadscrews is the same, regardless of the overall length. This is because the manufacturer does not give us a price break on the shorter screws (in fact, they wanted more for a 6″ ball screw). All screws come in at 400mm (15.75mm) long, and we cut them to length to fit the individual machine axis.
2. All retrofits come with the stepper-motor mount, coupling, bearings, preload nut, and ball screw fully assembled in our factory. We do not sell these parts individually for you to assemble.
3. The ball leadscrew and the rest of the assembly are assembled and checked in our factory. We place an O-ring on the end of the ball screw, below the saddle, away from the motor mount. The O-ring is placed there to help ensure that the ball nut does not thread itself off the ball screw. If the ball nut threads off the ball screw, the balls in the ball nut will come out. At this point, the ball screw is scrap. There is no way to fix it! For this reason, the O-ring is to remain on the ball screw until the ball screw assembly is fully assembled on your machine. After you have assembled your ball screw on your machine, you may remove the O-ring.

NOTE: On retrofits, the only way possible for your ball leadscrew to have excessive slop (backlash), is if some of the balls have come out of the ball nut. We will not replace ball leadscrews that have excessive slop (backlash)!