Click the questions below to find the answers.
How do I install the mill ball screw retrofit kits?
Click on the links below to see how to install the various ball screw retrofit kits on your mill.
Instructions: Mill Ball Leadscrew Retrofit Notice
Instructional video links: X/Y-axis Ball Screw Retrofit Install, or Retrofitting a Sherline Mill with a Z-Axis Ball Screw Column
Do you have written instructions for unpacking and assembling a complete ball screw mill?
Do I have to use your stepper motor mount and coupling?
Yes, you will have to use our stepper motor mount assembly. Because we have the ends of our ball leadscrew machined to fit the tapered end of our coupling, the end of the ball screw will not fit any other style of coupling. We also preload the bearings in the factory, so we are sure that they are done right and that the amount of backlash is at a minimum.
Can I use my own stepper motors?
Yes, if the stepper motors have a NEMA 23 frame, then they will fit on our stepper motor mount. Our coupling has a 1/4″ hole for the stepper motor shaft. If your shaft size is different, we can probably accommodate you with a custom coupling.
Can I use the Y-axis accordion covers from my original mill?
No, they will not work with the new mill saddle and ball leadscrews. The X/Y saddle is much taller on the ball screw mill than on the standard leadscrew mill, and therefore, the metal plates of the accordion covers were increased in size accordingly.
What are some practical benefits of using ball screws vs. leadscrews?
- There is virtually no backlash in the ball screws. Here are the specs for our ball leadscrews:
- Rolled Ball Screw with BSH Nut.10mm Diameter, 2mm Lead.C7 Accuracy, P1 Preload.
- The linear accuracy is 50 micrometers / 300mm. Inchs: Rounded up .002″ / 12.0″ = .00016 / 1.0″.
- Because of the lack of backlash, you can “climb mill” with the ball screws, whereas you have to “conventional mill” with the lead screw.
- Less chatter when cutting.
- A more accurate and smoother arc and radius cuts.
- The pitch of the ball screw is 2mm (.07874″), whereas the pitch of our leadscrews is either 3/8-20 (.050″ or 1.27mm ) or 10x1mm (1mm or .03937″). Therefore, you have a more significant travel distance per revolution.
- The ball nut and ball screw combination will give your machine a much smoother motion.
- The ball screw will also perform for a much longer time and show very little wear over time when compared to the lead screw.
For a more in-depth look at the benefits of ball screws, CLICK HERE.
Does the ball screw still allow for manual control?
The stepper motors have handwheels on them so you can do manual work. The only drawback is that the ball leadscrews only come in a metric pitch (10 x2mm). Therefore the handwheels only have metric graduations. This is not to say you can’t run an inch setup. Both our Linux and MASSO controllers can be set up, so the control screen is either inch or metric. You can also run metric programs using an inch control screen and vice versa.
NOTE: You cannot use the position screen on the controller when you are doing manual operations. Our stepper motors do not send position signals back to the controller; they only receive signals and execute moves.
The ball screws also are only available in a right-hand thread. This is not a problem for moving the machine manually, however the direction that a given axis moves may be opposite from our non-ball screw machines.
Can I adjust the backlash on the ball screws?
Yes. Click the Instruction links below to learn how to set your gibs and backlash on each axis.
Instructions: Setting the Gib & Backlash on Sherline Ball Screw Machines
Instructional video link: Replace, Assemble, and Adjust the X/Y-axes Mill Backlash
What is the difference between climb milling and conventional milling?
Roughing cuts and cutting hard materials should be done with “Conventional Milling.” Finish cuts can be done with “Climb Milling.” Climb milling is, as the name implies, the cutting edge of the tool that is literally climbing up the side of the part. Conventional milling has the cutting edge of the tool digging into the side of the part. For a detailed explanation of the difference between the two milling procedures, CLICK HERE.
What type of lubrication do you use on the ball leadscrews?
The ball screw manufacturer recommends NSK Grease AS2 for lubricating the ball leadscrews. Move the axis to the end of travel and put a minimal amount of grease on your fingertip. Apply it along the length of the leadscrew from the ball nut to the stepper motor mount.
Can I use a ball screw machine manually, and can the axes be locked?
Sherline ball screw machines (and the mill ball screw upgrade kits) are designed as full CNC machines. As a CNC machine, the axes lock in place when the stepper motors are energized. The power to the stepper motors can be turned off, which will enable the user to move an axis manually. We don’t offer axis locks for the ball screw machines in the CNC application because they don’t need them. Therefore you can’t lock an axis when using a ball screw machine as a strictly manual machine. Our manual machines have X- and Y-axis locks (P/N’s 40760 and 50190). Removing the locks on the ball screw machines was a safety consideration, so our customers would not inadvertently lock the axis (or forget to unlock the axis), and then try to operate the machine as a CNC with the locks on.
You can, however, lock any axis with the stepper motors energized. If you want to make a cut in the X-axis (as an example), turn the driver box* off, disconnect the X-axis stepper motor cable, then turn the driver box on so it energizes the Y- and Z-axes, then make your cut in the X-axis. The energized stepper motors will lock the Y- and Z-axes better than our Y- and Z-axes locks that are on our existing manual mills.
There is no significant movement of the axes with all of the stepper motors off, and there is absolutely no movement if you energize the steppers on the axes with which you are not going to machine.
NOTE: If you do not have a driver box (P/N 8760), you cannot energize the stepper motors.
I have an older CNC ball screw machine. Can I add limit switches to it?
Absolutely. We have developed limit switch retrofit packages for each axis on each of our machines that include the limit switches, mounting brackets, eccentric triggers, and other mounting hardware (click on the link below for complete parts list details). You just need to tell us what type of Sherline machine and leadscrew that you have, and what style column you have. You may then connect them to any controller that is configured to work with our limit switches.
Complete parts list: Sherline/MASSO Controller Part Information and Part Numbers
Instructions: Mill Limit Switch Mounting Retrofit Instructions, and Lathe Limit Switch Mounting Retrofit Instructions. Use the following instructions for adding the limit switch eccentric trigger stop for the X-axis on your Ball Screw mill: Retrofitting Your Ball Screw Mill with Limit Switches
Instructional video links: Mill Base Limit Switch Retrofit, and Installing Limit Switches on a Ball Screw Mill