Ball screw vs lead screw is a comparison of two ways to turn rotary motion into linear travel. For an aluminum cutting or positioning project, compare the identified assembly at the required load, stroke and operating sequence. A screw label does not establish the finished-part tolerance.
On this page
Ball screw vs lead screw: rolling and sliding contact
Thomson’s ball-screw information describes recirculating balls between the screw and nut. A lead screw uses sliding contact between its mating surfaces. Both arrangements convert rotation to linear movement; their contact mechanisms differ.
Ask the supplier to name the screw and nut as an assembly. “Screw driven” alone does not identify the technology, size, material or operating limits. A drawing should show where that assembly fits within the quoted axis.
Then name the function. Material advance, an adjustable stop and another positioning movement are different jobs. Do not transfer an axis description to the blade drive or assume that every CNC saw uses the same transmission.
Read the stepper versus servo guide for the separate motor-control comparison. The screw describes a mechanical transmission; the motor and feedback need their own identification.
Lead, pitch and a simple travel example
Thomson defines lead as the nut’s linear travel for one screw revolution. Pitch is the spacing between threads. The two values coincide for a single-start thread; with multiple starts, lead is pitch multiplied by the number of starts.
Use the actual lead when interpreting a travel statement. Ask for the units and the corresponding screw designation. Do not replace lead with the nominal diameter or assume that every screw has one start.
A fictional 100 mm movement
Imagine two invented screws with leads of 4 mm and 8 mm per revolution. Assume direct screw rotation and ignore mechanical and control errors for this arithmetic example.
| Lead | 100 mm ÷ lead |
|---|---|
| 4 mm per revolution | 25 revolutions |
| 8 mm per revolution | 12.5 revolutions |
The calculation describes an ideal geometric relationship. It supplies no machine speed, positioning accuracy or cutting output. Neither lead is a recommended size or a JiurunCut specification.
For a real quotation, have the supplier explain any gearing and how the commanded movement relates to the installed mechanism. Keep usable axis travel separate from screw length and finished-part length. Our feeding-stroke guide explains the purchasing terms.
Backlash and direction changes
Thomson’s ball-screw page explains that clearance in the screw–nut tracks can produce lost motion. It describes preloaded assemblies as a way to address that clearance. A ball-screw label alone does not state whether the offered assembly is preloaded.
The manufacturer’s lead-screw application article also discusses anti-backlash lead nuts. Such options exist, so do not assume that the technology name supplies a complete reversal-performance specification.
Ask what the supplier means by backlash, how it is specified and under which conditions it is checked. Keep that component requirement separate from the axis’s positioning result and the cut part’s dimensional report.
If your approved job changes direction, include that pattern in the application brief and agreed demonstration. Ask the supplier to document its method. Do not introduce a homemade adjustment or reversal procedure during an acceptance review.
Load, speed and operating pattern
Thomson’s application article links lead-screw performance to friction, nut material and the combination of loading, speed and duty. It discusses heat as a constraint on the operating pattern. A suitability review therefore needs those conditions together.
Provide the supplier with the moving assembly, travel sequence and intended use. State what information is known and what the responsible engineer must determine. Procurement should not invent a thrust rating from the stock’s weight alone.
Request the current limits and selection basis for the actual screw–nut package. Ask how the mounting arrangement, available travel and proposed operating pattern were reviewed. A catalog maximum without its conditions is incomplete comparison evidence.
Keep component limits separate from the machine promise. Even an appropriate screw package still needs integration with the chosen motor, guide, supports and controls. The completed task requires its own agreed checks.
Holding and lubrication questions
Thomson explains that backdriving behavior depends on the screw arrangement. Its application article describes lead-screw designs that can also be backdriven. Do not treat every lead screw as a self-locking device.
For any load-holding requirement, ask the machine supplier to identify the approved holding provisions and responsible engineering review. Do not remove a brake, defeat a control or rely on friction based on this comparison.
Lubrication also belongs to the selected assembly. Thomson distinguishes ball-screw lubrication requirements from material-specific lead-nut arrangements, including some internally lubricated plastic nuts.
Request the machine’s approved lubricant, application method, access instructions and maintenance schedule. Record who provides service support. Do not copy a general lubrication interval or dry-running claim onto a different nut or installation.
A useful quotation checklist
Give suppliers the same requirement sheet so that replies describe comparable assemblies. Use these five entries to locate missing information:
- Identity: screw, nut, lead and the quoted axis function.
- Interfaces: support arrangement, guide, motor connection and drawing revision.
- Operating scope: required movement, loads and approved job sequence.
- Evidence: stated component limits, axis checks and finished-task acceptance.
- Support: included documents, commissioning and approved maintenance provisions.
Mark a component-only offer clearly. A screw and nut price cannot be compared directly with a completed positioning-axis price. Ask which supports, connections, controls and services are included.
Use the aluminum rail-support guide when preparing the supporting member. A cut profile, a machined support and an assembled axis require different delivery records.
Review the assembled task
Bring the released part drawing and representative aluminum stock to the review. Identify the length reference, quantities and inspection method. Keep the exact offered configuration in the trial record.
Ask for an agreed movement sequence that reflects the job. Record axis observations and finished-part measurements separately. A smooth-looking motion or component clearance statement is not a measured cutting result.
Use the factory acceptance checklist to assign the checks. If a component changes after approval, ask for a documented review of the affected configuration and evidence before treating the replacement as equivalent.
Send JiurunCut your profile drawing and required cut sequence to discuss the cutting task. Request a configuration-specific explanation of the proposed positioning arrangement and its review scope.
Buyer questions
Does a ball screw guarantee more accurate cut parts?
Review the completed machine and defined part inspection. The transmission category alone does not establish that result.
Is screw lead the same as thread pitch?
They are equal for a single-start thread. Identify the number of starts and actual lead for other arrangements.
Are all lead screws self-locking?
No. Obtain the approved holding provisions for the particular assembly and application. Do not infer them from the category.
Can I use the same lubricant for both screw types?
Follow the approved documentation for the selected assembly. Nut material and installation conditions belong in that decision.