What is the difference between screw pitch and lead?



Pitch is the distance between screw threads and is commonly used with inch sized products and specified as threads per inch.


Lead is the linear travel the nut makes per one screw revolution and is how ball screws are typically specified.

For a single start thread, lead is equal to the pitch.  For multiple start screws the lead is the pitch multiplied by the number of starts.

What are the differences between rolled and ground ballscrews?

The difference between cold rolling screw (rolled screw) and grinding screw is as follows:
1. Different processing methods:
Cold-rolled ball screw is to cut grooves with a certain depth in polished rod material at first, and the groove spacing is equal to the wire spacing you want to process, and then roll them out with a rolling mill. On the basis of press rolling, the grinding screw uses a special cylindrical grinder to precisely process the arc groove with the same shape and size, and the cut groove is at the bottom of the arc groove.

Rolled ball screw is preferred over cutting (turning on a lathe) for lead screws. It involves pressing a round bar between a set of dies that roll the threads into it. It results in a harder surface with superior surface finish for lead screws. Rolled ball screw is also the most common process for ballscrews because it is more economical and sufficiently accurate for most industrial applications. Lead accuracy can be held to better than .003 inch/foot and longer lengths are possible than with ground ballscrews.

If higher accuracy is required, grinding should be considered. The grinding process can hold lead accuracy’s as tight as .0003 inch/foot or better. However, this process is much more expensive and the maximum length of screw is much shorter.

2. Different scope of application and cost:
The precision grade of rolling screw is below the average, which is suitable for ordinary equipment with low precision requirements. It has a short life, high efficiency and low cost. The precision grade of grinding screw is above average, which is suitable for CNC machine tools and other equipment with high precision requirements. It has high precision, long life and high efficiency, but the cost is also high.
3. Different appearance:
The cold-rolled screw rod is formed by extrusion, and the grinding grade is processed by grinding. Turning is not the same as grinding process, and naturally there are process marks after it comes out. Generally, the surface of cold-rolled screw rod is smooth and shiny, and the light reflection rate is high and dazzling. Grinding marks of grinding wheel can be seen carefully on the surface of grinding screw. In terms of appearance, the raceway groove of the turning grade screw rod is smooth, which is shallower than that of the grinding screw rod.

What may cause premature failure of ball screws or ball nuts?

In the working operation, the ball screw will always produce some friction. Under the appearance of these friction forces, the ball screw will wear to a certain extent. When the ball screw is used for a certain time, the ball screw will be damaged. This is the process of ball screw damage, but besides, there are other reasons that will cause ball screw damage, such as unreasonable use of staff. What are the reasons for ball screw damage?

1. The clearance of the ball screw guide rail is not appropriate.

When we install the ball screw, if the installation is not in place, the ball screw clearance may be too large. If this happens, when the ball screw is working, it will be easy to have a big impact. Under the influence of this situation, the wear speed of the ball screw will be greatly accelerated. If we want to solve this problem, we need to disassemble the ball screw and install it correctly.

2. Causes of lubrication

Before the ball screw is used, we need to lubricate it. At this time, some inexperienced novice employees may not be able to grasp the usage of lubricating oil. If the lubricating oil used by the novice ball screw is not enough, in this case, the ball screw will generate more friction when it is used, which will also have adverse effects on the ball screw. Therefore, at this time, the novice should add more lubricating oil to the ball screw for lubrication.

3.Excessive speed

Exceeding the ball nut critical speed can lead to pickup fingers breaking, which will allow to the ball bearings to come out of the nut. Exceeding the screw critical speed will cause the screw to whip or vibrate and cause misalignment. Shaft speeds resulting in screw surface speeds above 8,000 inches per minute will reduce rated life.

Why Ball screw will always be more expensive? Nearly 80% user will consider the price.

That’s easy – there are more parts. A lead screw is merely a threaded shaft and simple nut. The precision of such a device is based on the grind accuracy for the shaft and the resultant play when the nut is installed. The ball screw material is better and have special treatment. There is also have high requirement for the ballscrew precision. Usually the C7 grade can meet most need. For more precision machine C5 grade is will be requested.

What precision ball screws can we provide?

ARESWIN can supply the ball screw with nut C7 and C5 Grade,we provide the TAIWAN TBI,GTEN brand and made in China brand ballscrew, can meet different budget of clients need. We can machining the ends of screw base on the clients drawing.
We will recommend you the following type of  TBI ball screw,they can meet most needs,but price is cheaper.

TBI sfu ball screw supply

SFU type ball screw is flange type ball screw,widely used in 3D printer,CNC machine and robot industry. This type ball screw is normal type and price is cheap and easy to exchange the ball nut.

SFU1605 ballscrew diameter is 16mm and also have other type diameter,max length can reach 4 meters and the length can be customized.Cold rolling screw rod. We can supply TBI brand(made in Taiwan),which have the best quality. Also the made in China SFU1605 ball screw can meet the client need in most industrial machines.TBI brand ball screw have best perfotmance.


sfk ball screwThe SFK Serie of ball screw is a Miniature Ball screw serie with flange nut in diameter 8 -10mm, in Grade C7. This ball screw serie is always P1 clearance quality, with no axial play.






TBI MOTION Ball Screw SFV Series


The SFV Serie of ball screw has a single flange nut. It is made in Grade C7. This type of ballscrew is suitable for pressing applications or heavy load movements.




Double standard ball nuts DFU are perfect choice for applications where high durability, positioning accuracy and smooth operation is required. All nuts are axial play free with 0-2% preload which reflect in high rigidity. Preload can be adjusted on the nut. Ball nuts and screws has to be from the same producer! Every nut is tested to fit perfectly to the ball screw.

ball screw ofu dfu tbi

We can also supply the T type screw, the T type screw have cheap price and have big different with ball screw.

1.Ball screw: It has the characteristics of high precision, reversibility and high efficiency. Because of its small friction resistance, ballscrew is widely used in various industrial equipment and precision instruments.

2.Trapezoidal screw: A product with high efficiency, low cost, and low machining accuracy, whose structure design ideas and schemes are worth popularizing and applying.
The Trapezoidal screw have usually screw material is stainless and the nut is brass, wildly used in 3d printer and robot industry. The thread have left type and right type, and left and right in one screw. Usually, it no need to machining the ends of screw, in this way, the machining cost will no need and cost will be cheaper.

Meanwhile, the material type is cheaper than the ball screw raw material.The diameter have T8,T12,T6 type,which have a diameter 8mm,12mm,6mm. The pitch also have different types, pitch have 2-8mm, and lead can be 2 -12mm. The length also can be adjust,from 20mm to 2000mm.
The Trapezoidal screw price is cheaper than the ball screw, if you machine no need the high precision, T type screw is a good choice. It is easy assemble and wiely used also.
All in all, the price of ballscrew is expensive, but the it have best performance. The user can choose different types base on the need, ARESWIN will provide the solution for our clients need.We will provide techincal support and welcome inquiry us.

Constant Section Thin Walled Bearing

The Constant Section Thin Walled Bearing is a kind of bearing even if the shaft diameter and bearing bore are larger, the cross-section of the thin-walled bearings will remain unchanged, so they are also called equal-section thin-walled bearings.Thin-walled equi-section bearings, also called thin-walled ring bearings, have high precision, very quiet and strong bearing capacity. Thin-walled ring bearings can be deep groove ball bearings, four point contact bearings, angular contact ball bearings, thin-walled uniform section bearings cross section is mostly square.

Ultra-thin Wall Bearing With Equal Cross Section which is a thin-walled bearing composed of seven open series and five sealed series. There are three types of open series: radial contact, angular contact and point contact.


Thin-wall bearing realizes thin bearing section, and also realizes miniaturization and light weight of products. The diversity of products expands its application range.

Thin-wall bearing producibility:

In order to obtain low friction torque, high rigidity and good rotation accuracy of the bearing, steel balls with small outer diameters are used.The use of hollow shaft ensures light weight and wiring space. Thin-wall 6700 and 6800 series have all kinds of dust cover forms, flanged forms, stainless steel forms, wide forms, etc., all of which are of the same variety.

Main Applications:

Stepping motors, medical instruments, office instruments, testing instruments and speed reduction. Variable speed device, robot, optics,Imaging device, rotary encoder.


Product Description:

SGR series double-axis slide rail: the slide rail with U-shaped cross section is adopted, and the inner side of the slide rail is provided with an axis rail, and the slide block is arranged in the linear guide rail of its internal test structure.

SGR Double-Axis Guide Rail Advantages

1.Adjustable pressure:”zero” interval standard

2.Lower sensitive style of dust

3.Grind surface to install rail

4.We can change the length of round linear guide according to your requirements.

5.Quality quarante for accuracy and repetition

6.Guide rail or slide board and wheel can added according to the needs of customers

7.Higher speed noise volume

8.Higher speed target

Material: basically made of high quality aluminum alloy with oxidation treatment on surface, the optical axis is with chrome plated treatment on surface.


Built-in Double Axis Linear Guideway Model NO.As Below:

(1) SGR10    SGB10-3UU / SGB10-4UU/  SGB10-5UU

(2) SGR15    SGB15-3UU / SGB15-4UU / SGB15-5UU

(3) SGR15N  SGB15N-3UU / SGB15N-4UU / SGB15N-5UU

(4) SGR20     SGB20-3UU / SGB20-4UU / SGB20-5UU

(5) SGR20N   SGB20N-3UU / SGB20N-4UU / SGB20N-5UU

(6) SGR25     SGB25-3UU / SGB25-4UU / SGB25-5UU

(7) SGR35     SGB35-3UU / SGB35-4UU / SGB35-5UU

The Product Specifications:

Guide rail length: the MAX length of the whole rail is 4000mm, and docking can be carried out if the length exceeds 4000mm; Any length can be cut as required, and different specifications and prices are different.

Application area:

Built-in SGR and external LGD, two kinds of double-axis roller linear guides, belong to linear motion transmission products, which are widely used in precision machinery, flame cutting machine, computer engraving machine, fitness equipment, printing machinery, packaging machinery, textile machinery automatic production line and other machinery and supporting equipment.

linear module sliding table

The linear module sliding table is an important auxiliary equipment that many automation equipments need to use. The common automation equipments used in linear modules are: printing press, soldering machine, mechanical arm, etc.

So, what aspects should we pay attention to when purchasing the linear module sliding table?

The following three points should be noted:

1. Load

Linear modules usually need a certain amount of load, that is, how much weight the modules need to load. At present, many linear module manufacturers can offer products with various loads, and the factory must choose the linear module according to the actual load weight in the production process, otherwise, the load of the linear module will be insufficient, which will lead to problems in the product assembly line.

2. Stroke accuracy

Linear module manufacturers with abundant supply will provide many linear modules with different effective stroke specifications. Effective stroke refers to how long the interval demand of linear modules moves from one end to the other, which is also related to the basic requirement of which products the factory can use linear modules. The movement accuracy also needs the factory to choose according to the products, so the effective stroke movement accuracy is the factor that determines the linear module specifications when selecting the products of linear module manufacturers.

3. Configuration

The selection of linear modules should also proceed from the configuration point of view, such as the brand specifications of screw rods, guide rails, timing belts, switches, etc. The products of linear module manufacturers also have certain differences in configuration. When selecting, the configuration of linear modules should be determined according to the requirements of precision and other aspects when producing products.

What is the difference between ball screw and trapezoidal screw?

6. Different axial clearance and preloading methods.

Axial clearance is also a very important factor to consider when selecting lead screw, because the existence of clearance will lead to return error, which directly affects the accuracy of reverse operation. Ball screws are divided into different grades according to the gap. For example, THK is divided into G0(0 and preload), G1(0-0.005), GT(0-0.01), G2(0-0.02) and G3(0-0.05), and the axial clearance increases in turn. NSK is also divided into five grades, namely Z(0 and preload), T(0-0.005), S(0-0.02), N(0-0.05) and L(0-0.3). The values in brackets indicate the range of axial clearance in millimeters. For trapezoidal lead screw, Thomson shows that the axial clearance is between 0.02 mm and 0.25 mm. In order to eliminate the axial clearance between the nut and the screw shaft and improve the transmission accuracy, both ball screw and trapezoidal screw can increase the preload. However, the preloading methods are different. For example, THK and NSK ball screws use nut phase difference for a single nut, while for a double nut, they use pre-compression gaskets or spring plates for pre-compression. On the whole, the axial clearance is smaller for ball screws, and the preloading method is more for ball screws, because the current preloading methods for trapezoidal screws belong to constant pressure preloading method, while ball screws are two types: positioning preloading and constant pressure preloading.

7. Different calculation methods.

When calculating the ball screw, it is necessary to consider the basic conditions such as precision, speed and load required by the system. In which, constant speed torque: T1=(Ta+Tpmax+Tu)/i .. I= the number of teeth on the lead screw side N2/ the number of teeth on the motor side N1, indicating the reduction ratio. Generally, trapezoidal screw only needs a formula, T1=FP/2πη, because trapezoidal screw is suitable for low-speed applications, and there are no problems such as high-speed round trip and high acceleration and deceleration.

8. Structural design of nut decoupling.

When the lead screw is long, the nut is subjected to axial deflection torque or the nut is subjected to axial load, the lead screw shaft inclines or deforms along the radial direction, which may cause uneven stress, jam and vibration, which may lead to increased wear and affect the accuracy.

9. Differences in applications.

Trapezoidal screw is sliding friction, too high speed will produce high heat on the joint surface, which will lead to increased wear. Therefore, trapezoidal lead screw is suitable for applications with light weight and low speed requirement. At the same time, trapezoidal lead screw, because of its low precision, is often more suitable for applications that do not require high precision, such as slow transfer and handling. Ball screw, with low heat and high precision, is usually more suitable for applications requiring smooth motion, high efficiency, high precision and long-time continuous or high-speed motion, such as semiconductor equipment.

10. Example of calculation and selection of ball screw.

Finally, how to choose the ball screw according to the conditions of precision, speed, load and service life? “How to choose ball screw”, contact us and we will share it with you.

What is the difference between ball screw and trapezoidal screw?

When to use ball screw, When to use trapezoidal screw?

How to select ball screw (or trapezoidal screw) and motor according to the requirements of precision, speed and load?

What are the common forms of supporting structures at both ends? (fixed-supported)

What is the structural design of nut decoupling at long stroke?

Let’s look at the difference between ball screw and trapezoidal screw with these questions, and explain it roughly from the following 10 aspects.

1. Different structures.

The movement principle of trapezoidal screw and ball screw is the same, but the difference is that there is no ball in trapezoidal screw, so the movement between nut and screw shaft depends entirely on mechanical contact to produce sliding, which is sliding friction, so trapezoidal screw is also called sliding screw.

Therefore, the structural difference between the two is summarized in one sentence: the ball screw is rolling friction and the trapezoidal screw is sliding friction.

2. Different transmission efficiency.

For example, NSK and THK show that the friction coefficient of ball screw is between 0.003 and 0.01, while that of trapezoidal screw is between 0.1 and 0.2.

For example, REXROTH shows that the friction coefficient of ball screw is between 0.005 and 0.01, while that of trapezoidal screw is between 0.2 and 0.3.

This is why the transmission efficiency of most ball screws is as high as 90%, and some even reach more than 95%, while the transmission efficiency of most trapezoidal screws is lower than 70%. trapezoidal screw is not suitable for high-speed operation, and its maximum speed is generally not more than 3000RPM. And the ball screw, because it is rolling friction, does not generate so much heat, and its speed can reach very high, such as 10000RPM. The efficiency of ball screw is 2-4 times that of trapezoidal screw, so generally speaking, when the same lead is used to drive the same load, ball screw has more advantages.

3. Different self-locking

Theory shows that when the transmission efficiency of screw is greater than 50%, there is no self-locking, and when the transmission efficiency is less than 35%, there is self-locking. Therefore, ball screw has no self-locking, while trapezoidal screw has certain self-locking.

The trapezoidal screw shaft is also made of stainless steel or alloy steel. As for the nut, it is a little different from the ball screw. In many cases, the trapezoidal screw nut will use nonmetallic materials.

4. Different materials

The ball screw shaft is generally made of stainless steel or alloy steel, while the nut is generally made of copper, because copper can bear a large load and has a small friction coefficient, which has a certain self-lubricating effect. Just like some common linear bearing or plane skateboards, copper is also used, which is precisely the reason.

The trapezoidal screw shaft is also made of stainless steel or alloy steel. As for the nut, it is a little different from the ball screw. In many cases, the trapezoidal screw nut will use nonmetallic materials.

5. Different manufacturing methods and final precision

Generally, there are two processing methods for ball screws, one is grinding and the other is tying. The general precision of rolling ball screw is C7 C7(±50um/300mm), C8 C8(±100um/300mm) and C10 C10(±210um/300mm).C0-C5 belong to grinding grade screws, and the highest precision of grinding ball screws can reach C0 grade, that is, 3 um/100mm, and even ball screws with low grade C5 can achieve the precision of ±18um/100mm. Usually C5 and C3 (such as TBI and GTEN brands).

Trapezoidal screw has three manufacturing methods: rolling, cutting and grinding.

It is better than cutting, because rolling can get a harder surface with superior surface finish. However, as far as precision is concerned, grinding can obtain the highest precision, followed by cutting, and rolling can obtain the lowest precision.

For other differences, please see the next article.

What is the reason for the blackening of the coupling?

The coupling is used to connect the two shafts together. The two shafts cannot be separated when the machine is running. The two shafts can only be separated after the machine is stopped and the connection is disconnected. Do you know what are the classifications of couplings?

Let’s follow the editor to find out:

1. Rigid coupling: It can only transmit motion and torque, without other functions.

2. Coupling: It can transmit motion and torque, overload* protection, in addition, it also has different degrees of compensation performance, such as pin type, friction type, magnetic powder type, centrifugal type, hydraulic type and other couplings .

3. Flexible coupling: A flexible coupling without elastic elements can not only transmit motion and torque, but also have different degrees of axial, radial and angular compensation performance, including gear couplings, universal Toward couplings, chain couplings, slider couplings, etc.

4. Flexible coupling with elastic elements: it can transmit motion and torque; it has different degrees of axial, radial and angular compensation performance; it also has different degrees of damping and buffering effects to improve the work of the transmission system Performance, including flexible couplings with various non-metal elastic elements and flexible couplings with metal elastic elements. The structure of various elastic couplings is different, and the difference is large, and the role in the transmission system is also different.

The speed of the working coupling is high and low. For the two-shaft connection that needs high-speed operation, the structure of the coupling should be considered to have high balance accuracy characteristics to eliminate vibration and noise caused by centrifugal force, and increase the relevant drum-shaped gear coupling The abrasion and heat of the motor reduce the transmission quality and service life. Among them, the diaphragm coupling has better adaptability to high-speed operation.

The shaft system connected by the coupling and its operation. For the connection shaft system with large mass and large moment of inertia, and frequent starting, shifting or reversing, you should consider choosing a spring-elastic pin coupling that can withstand large instantaneous overloads and can buffer and absorb vibration.

When the entire diaphragm coupling enters some sending liquids, first of all, they may cause a series of corrosion to acidic objects, and may cause some dissolution of metals, or they may have various effects on some other ions. A different kind of displacement reaction. Then in this case, some of the original particles can replace each other and deposit on the metal surface, because some oxidants are added to the solution itself, so some different ions in the nitrite are reduced. This can effectively promote a series of oxidation reactions or other chemical reactions on their metal surfaces.