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Self-Reversing Screw/Level Winder Screw

Founded in 2011, LMT specializes in R&D, manufacturing, and sales of self-reversing screws, lead screws, and winches. The company holds ISO 9001 certification, is recognized as a High-Tech and Technology-Based Enterprise, and owns 15 utility model and 3 invention patents. Supported by the local government as a key enterprise, LMT exports its products to many regions worldwide.

Professional Custom Self Reversing Screw & Design Solution Expert

We specialize in the production of ball self-reversing screws,stainless steel self-reversing screws,miniature self-reversing screws,large self-reversing screws for ships and large ports,self-reversing screws for large winches,self-reversing screws for oilfield automatic coiling equipment,and polyformaldehyde self-reversing screws.

Leveraging over 15 years of industry experience,LMT serves as your trusted engineering and design partner.We produce strictly according to your drawings and specifications,and provide professional design support,custom scheme development and structure optimization.

Our team includes senior experts in self-reversing screw motion systems,as well as skilled engineers in non-standard automation equipment.They are highly professional in mechanical structure and self reversing screw design,with more than 500 successful projects completed.We fully evaluate the stability,durability and rationality of your design,find potential problems,and provide reliable customized solutions to improve your product performance.

LMT Popular Custom Options & Material Selections：

(1)Available diameter range:5mm~200mm

(2)Two main types of self-reversing screws:Self reversing ball screw(The nut contains steel balls),Self reversing lead screw(The nut contains a pawl）

(3)Self reversing screw material:C45,SS303,SS304,440C,SS316,SS316L,40Cr,titanium alloy,2507 duplex stainless steel,brass,GCr15,POM,nylon,38CrMoAl,42CrMo.
(4)Block nut material:Brass,bronze,aluminum,C45,SS303,SS304,440C,SS316,SS316L,40Cr,POM,PEEK,Nylon,Ductile Iron Castings,38CrMoAl,Naval Brass,42CrMo.

(5)Pawl material: Brass,Bronze,40Cr,42CrMo,2507 duplex stainless steel,C45

(6)Popular surface treatments:Passivation treatment,Electrolytic polishing,nickel plated,black coating,galvanize,chromeplate,nitrogenization
(7)Customized service:Self-reversing screw and nut block will be produced according to your requirements or drawings

Outstanding Enterprise in 2025 Self-Reversing Screw Manufacturer Evaluation
The China Transmission Machinery Association recently released its 2025 evaluation of self‑reversing screw (level winder screw) manufacturers.Over 100 companies were assessed across four weighted metrics: R&D (35%), product performance (30%), market application (20%), and service capability (15%). In this evaluation, LMT company stood out.The company holds ISO 9001 certification, is recognized as a High-Tech and Technology-Based Enterprise, and owns 15 utility model and 3 invention patents.Supported by the local government as a key enterprise, LMT exports its products to many regions worldwide.

Major Projects Powered by LMT Self-Reversing Screws
Our self-reversing screws are trusted by major global clients and have been integral to numerous large-scale and high-tech projects worldwide：
Major Infrastructure: Hong Kong-Zhuhai-Macao Bridge Construction Project.
Scientific Research: The Chinese Academy of Sciences (CAS),Nanjing University,and the Xi'an Aerospace Research Institute.
Global Industry Leaders: CNPC(China National Petroleum Corporation),Sinopec,and various clients in the USA,Canada,and the UAE for oil,marine,and machine tool applications.

Industrial Applications of LMT Self-Reversing Screws
Our level winder screws are engineered for performance in a wide array of fields, such as:
Industrial Machinery: Machine Tools,Steel Coiling,Hydraulic Presses,Packaging Machinery,Printing Machinery,Endoscope Debris Removal Robot.
Marine & Offshore: Ships,Oil Pumps,Marine Mining,Port Equipment.
Specialized Equipment: Automated Spray Painting Machines,Tethered Drones,High-rise Building Window Cleaning Machines.
Other Sectors: Textile, Military Machinery,Agricultural Sprayers.

What is a Self-Reversing Screw?

Self-reversing screws are commonly known as level winder screws,reverse spooling screws,or diamond screws.Unlike lead screws or ball screws,which require the screw to reverse rotation direction for the nut to return to its starting point, a self-reversing screw operates with continuous unidirectional rotation. As the nut reaches one end of the screw, it automatically reverses direction and travels back.

How Does a Self-Reversing Lead Screw Work?

A self reversing lead screw assembly consists of three parts: the self reversing screw shaft,the pawl(follower blade),and the block nut.A self reversing screw shaft consists of two threaded grooves with identical pitches and opposite directions of rotation, connected by a transition curve to form a closed helical track; motion is converted by the thrust exerted by the helical flanks on the block nut.

When the screw is driven to rotate unidirectionally by a power source,the side of the spiral groove exerts a continuous thrust on the pawl,pushing the pawl and nut block to move axially along the self reversing screw shaft.

Without changing the rotation direction of the self reversing screw,the pawl and nut block can automatically move in the reverse direction,thus realizing continuous axial reciprocating motion.This design not only simplifies the transmission structure but also avoids the impact caused by frequent commutation of the motor,ensuring stable and smooth operation.

LMT Launches Innovative Ball Self-Reversing Screw

The internal circulation type of a conventional self-reversing screw features a nut with a built-in ball recirculation channel, which must be fully populated with balls. In standard ball screws, the number of balls typically exceeds ten, and an S-shaped reverse deflector is incorporated into the recirculation channel to enable internal ball circulation. This results in a relatively complex structure, high processing difficulty, a large number of balls, and a high coefficient of friction. During operation, significant frictional forces are generated, which can lead to localized overheating, loss of precision, and a reduced service life.

LMT addresses these issues by incorporating a positioning groove at the center of the concave surface of the first slider, and annular reversing grooves on the concave surfaces of two second sliders within the slide assembly. Together with the specially shaped thread groove on the screw, this design reduces the number of balls required for the linear reciprocating motion of the slide assembly to just three. This directly minimizes the contact points between the balls, the screw, and the slide assembly, thereby significantly lowering the friction coefficient among the slide assembly, the balls, and the screw, and consequently extending the service life of the mechanism.

Available Materials for Self-reversing Screws and Block Nuts

Self reversing screw material:C45,SS303,SS304,440C,SS316,SS316L,40Cr,titanium alloy,2507 duplex stainless steel,GCr15,POM,nylon,38CrMoAl.
Block nut material: brass,bronze,aluminum,C45 steel,SS303,SS304,440C,SS316, SS316L,40Cr,POM,PEEK,Nylon,Ductile Iron Castings,38CrMoAl.

Custom Self-Reversing Screw Coatings & Surface Treatments

To maximize the durability and performance of your self-reversing screws,LMT provides a range of custom surface coating options. Our advanced treatments protect against wear,corrosion,and friction,ensuring reliable operation.Popular coatings for self-reversing screws:Galvanized,blackening,nitrogen treatment,chromeplate,nickel plating.

With 15 years of specialized experience in producing self-reversing screws our factory offers an extensive selection of over 1000 different models to meet diverse application needs. We have successfully participated in more than 500 projects and served 100+ customers across various industries. Our commitment to precision manufacturing and reliable performance makes us a trusted partner for your drive and motion control solutions.

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manufacturing experience

500

Projects

1000

Model number of Self-reversing screw

100

our customers

What Services Does LMT Provide?

Quick Response

We will send a quote and respond to any customer request within 24 hours.

Design & Optimization Services:

We assist customers in designing self-reversing screws and optimizing their current designs to achieve better performance and reliability.

Competitive Price

We will help you save 25% to 50% on your project.

100% Product Inspection

All self reversing screws will be tested by professional inspectors before shipment to ensure quality.

Customized Service

Self reversing screw and nut will be manufactured according to customers' requirements or drawings. MOQ 1 pc.

Fast Delivery

Lead time is within 15days.

How Does LMT Control the Quality of Self-reversing Screw Assembly?

1. Raw Material Control
We purchase raw materials only from qualified high-quality suppliers. Each batch of materials has complete material certification,material test report and quality inspection certificate.
2. Professional Testing
We use professional testing equipment and tools to strictly inspect product size, appearance and performance.
3. 100% Double Inspection
Every self-reversing screw goes through 100% inspection. First, the factory conducts initial inspection; then the export department does secondary inspection. Products are delivered only after both inspections are passed and results are confirmed correct.
4. Operation & Function Test Videos
We will send customers operation videos of self-reversing screws,pawl and nuts,together with function test videos and pictures.
5. Product & Packaging Details Confirmation
We will send customers detailed product pictures and all packaging pictures before shipment to ensure all details meet customer requirements.

How to Get a Custom Self-reversing Screw and Block Nut?

Simply send us your drawings or specifications.We can produce self-reversing screws and block nuts according to your drawings and requirements.You can also send us your needs, and our team will assist you with design.

Latest News

Self-reversing Screw

What Makes LMT The Top Choice for Self-Reversing & Level Winder Screws？

For businesses seeking reliable,high performance self-reversing screws backed by professional expertise and consistent quality,LMT stands out as the top choice.

06/12/2025

Self-reversing Screw

Self-reversing Screw

How Does LMT Control The Quality of Self-reversing Screw Assembly?

As critical precision components in various mechanical transmission systems,self-reversing screws directly determine the operational stability, transmission accuracy and service life of complete sets of equipment.

06/04/2026

Self-reversing Screw

2025 Self-Reversing Screw & Level Winder Screw: Top Manufacturers for Technical Excellence & Market Reputation

The China Transmission Machinery Association recently released its 2025 evaluation of self‑reversing screw(level winder screw)manufacturers.Over 100 companies were assessed across four weighted metrics:R&D (35%),product performance(30%),market application(20%),and service capability (15%).

03/01/2025

Self-reversing Screw

How Does A Self Reversing Screw Work?

A self reversing screw assembly consists of three parts: the self reversing screw shaft,the pawl(follower blade),and the block nut.The operating principle of self reversing screw mainly relies on its unique spiral groove design.

03/02/2026

Self-reversing Screw

What are the key differences between self reversing screw, lead screw and ball screw?

Lead screws and ball screws require the driven screw to change its direction of rotation in order for the nut to return to its original starting position.In contrast,a self-reversing screw operates with continuous unidirectional rotation.

03/04/2026

Self-reversing Screw

What Is a Self-Reversing Screw Assembly?

A self reversing screw assembly,also known as a level winder screw assembly,reverse spooling screw assembly or diamond screw assembly,is a precision component that achieves mechanical transmission through a helical groove structure.Its core feature is that when the screw shaft rotates in one direction,it drives the block nut to perform axial reciprocating motion.A self reversing screw assembly consists of three parts: the self reversing screw shaft, the pawl(follower blade), and the block nut.

10/12/2023

Self-reversing Screw

Material Selection Guide for Self-Reversing Screws in Freshwater Environments

In the realm of custom reciprocating screws,there is no single "best" material—only the material best suited for the specific application.The analysis above provides a brief overview.

11/01/2024

Self-reversing Screw

Electropolish vs. Mechanical Polish: Which is Best for Your Self Reversing Screw?

During low-speed operation,the self-reversing screw drive system may exhibit stick-slip motion—characterized by intermittent movement and uneven speed—which affects positioning accuracy and motion stability.

11/03/2026

Self-reversing Screw