Mill Ball Screw Z-Axis Retrofit Kit


4 week lead time

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:

  • *Will you be using Sherline’s CNC driver box?
  • Please also indicate if you have a manual machine or CNC

Product Description

Key Upgrade Parts

The key upgrade parts for this ball screw retrofit kit include a ball leadscrew, stepper motor high-torque 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 ON THE COLUMN BED: 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 column saddle Z-axis ball nut mount (P/N 45046) 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 usable Z-axis travel, and the maximum clearance above the table will be 2″ less than that of a standard leadscrew machine. In order to achieve greater travel and clearance above the table, we suggest that you upgrade to the 15″ Extended Mill Column Bed (P/N 45261) if you are ordering a new machine or doing a mill ball screw retrofit. The 15″ extended column bed makes up for the loss of travel in the Z-axis. It is also available with an electroless nickel/Teflon plating (P/N 45265) that adds increased lubricity and rust prevention.

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, high-torque 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 your ball leadscrew can 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)!

The improper use of machine tools and their accessories can result in serious injury. Before using this tool, thoroughly read the instructions and make sure you understand its proper and safe use.


Always wear safety glasses when operating machine tools.

Download PDF Mill Ball Screw Retrofit Instructions

Instructions PDF Download

Download PDF 6800 Z-axis Exploded View

Instructions PDF Download

Download PDF Ball Screw Mill Unpacking and Assembly Notice

Instructions PDF Download

Download PDF Ball Screw Upgrade Benefits

Instructions PDF Download

Download Lubrication for Ball Screw Machines PDF

Instructions PDF Download

Download Ball Screw Lubrication PDF

Instructions PDF Download

Video instructions on how to retrofit a Sherline Mill with a Z-Axis Ball Screw Column

45165/11″, 45295/15″ Ball Nut Leadscrew 10 x 2mm, Z-Axis (cut to length)
67101 Stepper Motor Mount (with 3 mounting holes)
671052 CNC Coupling
67120 Stepper Motor Preload Bearings
67115 5-40 x 7/8″ SKT HD Cap Screw
67111 8-32 X 7/8″ SHCS
67106 CNC RH Coupling Preload nut (course)
45045 Vertical Milling Column Saddle for Ball Leadscrews
45046 Column Saddle Z-Axis Ball Nut Mount
40990 Column Gib (Full Length with ends cut off)
40900 82 deg x 3/8″ Flat Head Screw
45035 Motor Mount to Bed Adapter for Ball Screws
58508 X/Y & Z Ball Nut Mount
34095 Z-Axis 2-1/2″ Handwheel (2mm laser engraved lines)
40730 10-32 x 2″ SHCS
40330 10-32 x 5/8″ SHCS
40690 10-32 x 3/4″ SHCS
40660 #10 Washer
58512 Ball Screw Template Y-Axis
58513 Ball Screw Template X-Axis
12050 8-32 X 3/8″ SHCS
40570 3/32 Hex Key
Optional additional upgrade parts are:
56442 “Arm Mount” for Ball Screw
67126 Stepper Motors 2-Amp High Torque
3455 X/Z-Axis 2-/2″ Adjustable Handwheel (2mm laser engraved lines)
45265 15″ Column Bed (Electroless Nickel with Teflon Plated)
For optimal performance, we recommend using the High-Torque Stepper Motors with our Ball Screws.