How to find the right Linear Motion Ball Screws AI guide
Written by an AI model from its trained knowledge.
What the AI looks for in Linear Motion Ball Screws
- Rolled vs ground
- Rolled screws are typically accuracy grade C7 to C10. Ground screws are C5 or better. For hobby CNC, rolled C7 is fine. Precision machines need ground screws for consistent lead accuracy.
- Diameter and lead designation
- Codes such as SFU1605 mean a 16 mm diameter and a 5 mm lead. Match the nut, end supports and coupler to those numbers. Lead sets resolution and speed per motor revolution, and diameter sets stiffness and the critical speed over long lengths.
- End machining and supports
- Confirm the ends are machined to suit standard fixed and floating supports, for example BK and BF pairs sized to the screw. An unmachined screw needs a lathe before it can be mounted.
- Backlash and preload
- Use a preloaded or double nut where reversing accuracy matters. A single nut has some axial play, which shows up as lost motion on direction changes.
- Critical speed for long screws
- Long, thin screws have a lower safe rotational speed, so increase the diameter or use a fixed-fixed mounting as length grows. Exceeding critical speed causes whip and vibration.
Brands that matter
- HIWIN: Major maker of rolled and ground ball screws.
- THK: Premium precision ball screws.
- NSK: Precision ball screws for machine tools.
- TBI Motion: Mid-priced ball screws and support units.
What to avoid
- Removing the ball nut from the screw without a retaining sleeve, because the balls fall out.
- Kits that do not state the accuracy grade or lead.
- Exposed screws with no wipers or covers in dusty or chip-heavy environments.
Questions
Ball screw or lead screw?
Ball screws are more efficient, longer-lived and suited to CNC loads, but they can back-drive under gravity. Lead screws are cheaper and quieter, and with low leads they are often self-locking.