A ground ball screw can be configured for a particular machine, but "customized" does not mean that every diameter, lead, accuracy grade, nut and preload level can be combined freely. Each requested parameter affects manufacturing feasibility, load capacity, rigidity, speed, running torque and cost.
The most practical approach is to begin with the machine's performance requirements and installation drawing. The supplier can then confirm which standard components can be used and which dimensions require non-standard production.
Article contents
What Can Be Customized on a Ground Ball Screw?
Ground ball screw customization normally covers the screw dimensions, accuracy requirement, nut configuration and the interfaces connecting the assembly to the machine. Availability must be checked as a complete combination rather than parameter by parameter.
| Parameter | Possible Customization | What the Buyer Should Confirm |
|---|---|---|
| Accuracy grade | C3, C5 and project-based alternatives | Travel accuracy, repeatability and inspection requirement |
| Diameter and lead | Selection from compatible ground screw series | Axial load, speed, motor speed and required linear travel per revolution |
| Shaft length | Cut and produced according to the approved drawing | Overall length, threaded length, usable stroke and support distance |
| Nut configuration | Flanged, cylindrical, single-nut or double-nut structures where compatible | Mounting space, flange orientation, load direction and rigidity |
| Preload or clearance | Non-preloaded or preloaded configurations, subject to the selected series | Permissible axial play, required rigidity and acceptable running torque |
| End machining | Bearing seats, shoulders, threads, locknut sections, flats and coupling ends | Complete dimensions, tolerances, datums and matching component models |
| Support components | Matching BK/BF, FK/FF, EK/EF or other evaluated support arrangements | Mounting direction, bearing arrangement, load and installation space |
| Inspection documents | Dimensional or lead-accuracy documentation when agreed before production | Required inspection items, reporting format and acceptance criteria |
DLY's published precision ground ball screw range includes multiple diameters, leads, nut structures and accuracy grades. However, a requested combination must still be reviewed against the required length, preload and end-machining design. See the current Precision Ground Ball Screw product page for the available product direction.
Accuracy, Preload and Backlash Are Different Specifications
These terms are often combined in enquiries, but they describe different aspects of ball screw performance.
- Lead accuracy describes how closely the nut's actual linear travel follows the nominal travel over a specified distance.
- Axial clearance is the free axial movement between the screw and nut before the direction of force is reversed.
- Preload applies an internal load to reduce axial play and increase rigidity, but it can also increase running torque and heat.
- Machine positioning accuracy also depends on the bearings, alignment, frame rigidity, motor control, encoder resolution and temperature.
As a practical DLY reference, C3 is approximately ±0.008 mm per 300 mm and C5 is approximately ±0.018 mm per 300 mm under the applicable inspection conditions. These values describe screw lead deviation; they are not a guarantee of complete machine accuracy.
A C3 screw is therefore not automatically the correct choice for every precision axis. If the machine only needs C5 performance, specifying C3 may add cost without producing a measurable improvement in the finished equipment. A more detailed explanation is available in What Is the Accuracy of a Ground Ball Screw? C3 and C5 Explained.
Selection note: Do not request "zero backlash" without defining the actual permissible axial play, rigidity and running-torque requirement. The suitable preload depends on the screw size, nut structure, operating speed and thermal conditions.
End Machining Must Match the Bearings and Coupling
End machining is one of the most important parts of a custom ground ball screw. Even when the screw diameter, lead and accuracy are correct, the assembly cannot be installed properly if the bearing seats, shoulders, threads or coupling end do not match the machine.
A usable shaft-end drawing should identify:
- The fixed-side and supported-side dimensions
- Bearing seat diameters and fit tolerances
- Shoulder positions and relevant reference datums
- Thread size, direction and effective thread length
- Locknut, spacer and retaining-ring interfaces
- Coupling bore, keyway or flat requirements
- Required runout, concentricity or other critical acceptance tolerances
If standard support units such as BK/BF, FK/FF or EK/EF will be used, their exact models should be selected before the shaft-end drawing is approved. Support-unit names alone are insufficient because different sizes use different bearing-seat dimensions.
For a replacement screw, sending only the overall length is risky. The original drawing or a fully measured sample should be used to confirm the thread length, journal sizes, shoulders and installation datums.
Information Required for an Accurate Quotation
A clear technical enquiry reduces repeated confirmation and helps determine whether the requirement can use an existing series or needs a non-standard design.
For new equipment, a dimensioned 2D drawing is normally more useful than a photograph. For a replacement project, provide the existing model number, original drawing or sample dimensions and describe the reason for replacement.
How to Avoid Unnecessary Customization
Custom manufacturing is valuable when it solves a real installation or performance requirement. It should not be used simply because a parameter can be changed.
- Select diameter and lead from a compatible existing series whenever possible.
- Specify the required travel error instead of automatically requesting the highest accuracy grade.
- Define acceptable axial clearance and rigidity before deciding on preload.
- Finalize support bearings and coupling interfaces before approving end machining.
- Agree on inspection documents and acceptance criteria before production begins.
This approach usually provides a more reliable result than independently selecting the highest grade, strongest preload or most unusual dimensions. The final ball screw should be treated as part of the complete motion axis rather than as an isolated component.
Need a Custom Ground Ball Screw?
Send DLY your application requirements and shaft-end drawing for model, accuracy, preload and machining confirmation.
Email: export@dlybearing.com | WhatsApp: +86 189 5707 0963
