Tag Archives: precision gear

China Good quality CZPT High Precision Alloy Helical Gear Wheel near me shop

Product Description

1.Product Description
Gear shaft, Herringbone Gear Shaft, Bevel Gear, Eccentric Shaft mainly used on vessel engine, fan internal gear

1.1. Bevel Gear, Pinion Shaft Processing
Gear drawing— Simulation Modelling—Making casting model—Casting— Primary Detection—Rough machining—Hardening Tempering—Semi-finishing machining —Hobbing—Tooth Surface Quenching—Gear grinding—Gear Surface Carburzing—Inspection—Spray Anti-rust Oil—Package—Delivery
Gear Shaft drawing CHECK, Make Forging Mold, Forging Mold Quality Inspection Check, Machine Processing, Check Size\Hardness\Surface Finish and other technical parameters on drawing. 
2.2. Bevel Gear Package
Spray anti-rust oil on Herringbone Gear Shaft, Wrap waterproof cloth around Gear Shaft for reducer, Prepare package by shaft shape&weight to choose steel frame, steel support or wooden box etc.
1.3. OEM Customized Pinion Shaft
We supply OEM SERVICE, customized herringbone gear shaft with big module, more than 1tons big weight, more than 3m length, 42CrMo/35CrMo or your specified required material gear shaft. 

2.Product Technical info.

Module m Range: 5~70
Gear Teeth Number z OEM by drawing’s technical parameters
Teeth Height H OEM by drawing’s technical parameters
Teeth Thickness S OEM by drawing’s technical parameters
Tooth pitch P OEM by drawing’s technical parameters
Tooth addendum Ha OEM by drawing’s technical parameters
Tooth dedendum Hf OEM by drawing’s technical parameters
Working height h’ OEM by drawing’s technical parameters
Bottom clearance C OEM by drawing’s technical parameters
Pressure Angle α OEM by drawing’s technical parameters
Helix Angle,    OEM by drawing’s technical parameters
Surface hardness HRC Range: HRC 50~HRC63(Quenching)
Hardness: HB Range: HB150~HB280; Hardening Tempering/ Hardened Tooth Surface 
Surface finish   Range: Ra1.6~Ra3.2
Tooth surface roughness Ra Range: ≥0.4
Gear Accuracy Grade   Grade Range: 5-6-7-8-9 (ISO 1328)
Diameter D Range: 1m~16m
Weight Kg Range: Min. 100kg~Max. 80tons Single Piece
Gear Position   Internal/External Gear
Toothed Portion Shape   Spur Gear/Bevel/Spiral/Helical/Straight
Shaft shape   Herringbone Gear Shaft / Gear Shaft / Eccentric Shaft / Spur Gear / Girth Gear / Gear Wheel
Material Forging/
Casting
Forging/ Casting 45/42CrMo/40Cr or OEM
Manufacturing Method   Cut Gear
Gear Teeth Milling  
Gear Teeth Grinding  
Heat Treatment   Quenching /Carburizing
Sand Blasting   Null
Testing   UT\MT
Trademark   TOTEM/OEM
Application   Gearbox, Reducer,
Petroleum,Cement,Mining,Metallurgy etc.
Wind driven generator,vertical mill reducer,oil rig helical gear,petroleum slurry pump gear shaft
Transport Package   Export package (wooden box, steel frame etc.)
Origin   China
HS Code   8483409000

Material Comparison List

 STEEL CODE GRADES COMPARISON
CHINA/GB ISO ГΟСТ ASTM JIS DIN
45 C45E4 45 1045 S45C CK45
40Cr 41Cr4 40X 5140 SCr440 41Cr4
20CrMo 18CrMo4 20ХМ 4118 SCM22 25CrMo4
42CrMo 42CrMo4 38XM 4140 SCM440 42CrMo4
20CrMnTi   18XГT   SMK22  
20Cr2Ni4   20X2H4A      
20CrNiMo 20CrNiMo2 20XHM 8720 SNCM220 21NiCrMo2
40CrNiMoA   40XH2MA/
40XHMA
4340 SNCM439 40NiCrMo6/
36NiCrMo4
20CrNi2Mo 20NiCrMo7 20XH2MA 4320 SNCM420  

3.Totem Service

TOTEM Machinery focus on supplying GEAR SHAFT, ECCENTRIC SHAFT, HERRINGBONE GEAR, BEVEL GEAR, INTERNAL GEAR and other parts for transmission devices & equipments(large industrial reducers & drivers). Which were mainly used in the fields of port facilities, cement, mining, metallurgical industry etc. We invested in several machine processing factories,forging factories and casting factories,relies on these strong reliable and high-quality supplier network, to let our customers worry free. 

TOTEM Philosophy: Quality-No.1, Integrity- No.1, Service- No.1 

24hrs Salesman on-line, guarantee quick and positive feedback. Experienced and Professional Forwarder Guarantee Log. transportation.

4.About TOTEM

1. Workshop & Processing Strength

2. Testing Facilities

3. Customer Inspection & Shipping

5. Contact Us

ZheJiang CZPT Machinery Co.,Ltd
 
Facebook: ZheJiang Totem

 

Screw Shaft Features Explained

When choosing the screw shaft for your application, you should consider the features of the screws: threads, lead, pitch, helix angle, and more. You may be wondering what these features mean and how they affect the screw’s performance. This article explains the differences between these factors. The following are the features that affect the performance of screws and their properties. You can use these to make an informed decision and purchase the right screw. You can learn more about these features by reading the following articles.

Threads

The major diameter of a screw thread is the larger of the 2 extreme diameters. The major diameter of a screw is also known as the outside diameter. This dimension can’t be directly measured, but can be determined by measuring the distance between adjacent sides of the thread. In addition, the mean area of a screw thread is known as the pitch. The diameter of the thread and pitch line are directly proportional to the overall size of the screw.
The threads are classified by the diameter and pitch. The major diameter of a screw shaft has the largest number of threads; the smaller diameter is called the minor diameter. The thread angle, also known as the helix angle, is measured perpendicular to the axis of the screw. The major diameter is the largest part of the screw; the minor diameter is the lower end of the screw. The thread angle is the half distance between the major and minor diameters. The minor diameter is the outer surface of the screw, while the top surface corresponds to the major diameter.
The pitch is measured at the crest of a thread. In other words, a 16-pitch thread has a diameter of 1 sixteenth of the screw shaft’s diameter. The actual diameter is 0.03125 inches. Moreover, a large number of manufacturers use this measurement to determine the thread pitch. The pitch diameter is a critical factor in successful mating of male and female threads. So, when determining the pitch diameter, you need to check the thread pitch plate of a screw.
screwshaft

Lead

In screw shaft applications, a solid, corrosion-resistant material is an important requirement. Lead screws are a robust choice, which ensure shaft direction accuracy. This material is widely used in lathes and measuring instruments. They have black oxide coatings and are suited for environments where rusting is not acceptable. These screws are also relatively inexpensive. Here are some advantages of lead screws. They are highly durable, cost-effective, and offer high reliability.
A lead screw system may have multiple starts, or threads that run parallel to each other. The lead is the distance the nut travels along the shaft during a single revolution. The smaller the lead, the tighter the thread. The lead can also be expressed as the pitch, which is the distance between adjacent thread crests or troughs. A lead screw has a smaller pitch than a nut, and the smaller the lead, the greater its linear speed.
When choosing lead screws, the critical speed is the maximum number of revolutions per minute. This is determined by the minor diameter of the shaft and its length. The critical speed should never be exceeded or the lead will become distorted or cracked. The recommended operational speed is around 80 percent of the evaluated critical speed. Moreover, the lead screw must be properly aligned to avoid excessive vibrations. In addition, the screw pitch must be within the design tolerance of the shaft.

Pitch

The pitch of a screw shaft can be viewed as the distance between the crest of a thread and the surface where the threads meet. In mathematics, the pitch is equivalent to the length of 1 wavelength. The pitch of a screw shaft also relates to the diameter of the threads. In the following, the pitch of a screw is explained. It is important to note that the pitch of a screw is not a metric measurement. In the following, we will define the 2 terms and discuss how they relate to 1 another.
A screw’s pitch is not the same in all countries. The United Kingdom, Canada, and the United States have standardized screw threads according to the UN system. Therefore, there is a need to specify the pitch of a screw shaft when a screw is being manufactured. The standardization of pitch and diameter has also reduced the cost of screw manufacturing. Nevertheless, screw threads are still expensive. The United Kingdom, Canada, and the United States have introduced a system for the calculation of screw pitch.
The pitch of a lead screw is the same as that of a lead screw. The diameter is 0.25 inches and the circumference is 0.79 inches. When calculating the mechanical advantage of a screw, divide the diameter by its pitch. The larger the pitch, the more threads the screw has, increasing its critical speed and stiffness. The pitch of a screw shaft is also proportional to the number of starts in the shaft.

Helix angle

The helix angle of a screw shaft is the angle formed between the circumference of the cylinder and its helix. Both of these angles must be equal to 90 degrees. The larger the lead angle, the smaller the helix angle. Some reference materials refer to angle B as the helix angle. However, the actual angle is derived from calculating the screw geometry. Read on for more information. Listed below are some of the differences between helix angles and lead angles.
High helix screws have a long lead. This length reduces the number of effective turns of the screw. Because of this, fine pitch screws are usually used for small movements. A typical example is a 16-mm x 5-inch screw. Another example of a fine pitch screw is a 12x2mm screw. It is used for small moves. This type of screw has a lower lead angle than a high-helix screw.
A screw’s helix angle refers to the relative angle of the flight of the helix to the plane of the screw axis. While screw helix angles are not often altered from the standard square pitch, they can have an effect on processing. Changing the helix angle is more common in two-stage screws, special mixing screws, and metering screws. When a screw is designed for this function, it should be able to handle the materials it is made of.
screwshaft

Size

The diameter of a screw is its diameter, measured from the head to the shaft. Screw diameters are standardized by the American Society of Mechanical Engineers. The diameters of screws range from 3/50 inches to 16 inches, and more recently, fractions of an inch have been added. However, shaft diameters may vary depending on the job, so it is important to know the right size for the job. The size chart below shows the common sizes for screws.
Screws are generally referred to by their gauge, which is the major diameter. Screws with a major diameter less than a quarter of an inch are usually labeled as #0 to #14 and larger screws are labeled as sizes in fractions of an inch. There are also decimal equivalents of each screw size. These measurements will help you choose the correct size for your project. The screws with the smaller diameters were not tested.
In the previous section, we described the different shaft sizes and their specifications. These screw sizes are usually indicated by fractions of an inch, followed by a number of threads per inch. For example, a ten-inch screw has a shaft size of 2” with a thread pitch of 1/4″, and it has a diameter of 2 inches. This screw is welded to a two-inch Sch. 40 pipe. Alternatively, it can be welded to a 9-inch O.A.L. pipe.
screwshaft

Shape

Screws come in a wide variety of sizes and shapes, from the size of a quarter to the diameter of a U.S. quarter. Screws’ main function is to hold objects together and to translate torque into linear force. The shape of a screw shaft, if it is round, is the primary characteristic used to define its use. The following chart shows how the screw shaft differs from a quarter:
The shape of a screw shaft is determined by 2 features: its major diameter, or distance from the outer edge of the thread on 1 side to the inner smooth surface of the shaft. These are generally 2 to 16 millimeters in diameter. Screw shafts can have either a fully threaded shank or a half-threaded shank, with the latter providing better stability. Regardless of whether the screw shaft is round or domed, it is important to understand the different characteristics of a screw before attempting to install it into a project.
The screw shaft’s diameter is also important to its application. The ball circle diameter refers to the distance between the center of 2 opposite balls in contact with the grooves. The root diameter, on the other hand, refers to the distance between the bottommost grooves of the screw shaft. These are the 2 main measurements that define the screw’s overall size. Pitch and nominal diameter are important measurements for a screw’s performance in a particular application.

Lubrication

In most cases, lubrication of a screw shaft is accomplished with grease. Grease is made up of mineral or synthetic oil, thickening agent, and additives. The thickening agent can be a variety of different substances, including lithium, bentonite, aluminum, and barium complexes. A common classification for lubricating grease is NLGI Grade. While this may not be necessary when specifying the type of grease to use for a particular application, it is a useful qualitative measure.
When selecting a lubricant for a screw shaft, the operating temperature and the speed of the shaft determine the type of oil to use. Too much oil can result in heat buildup, while too little can lead to excessive wear and friction. The proper lubrication of a screw shaft directly affects the temperature rise of a ball screw, and the life of the assembly. To ensure the proper lubrication, follow the guidelines below.
Ideally, a low lubrication level is appropriate for medium-sized feed stuff factories. High lubrication level is appropriate for larger feed stuff factories. However, in low-speed applications, the lubrication level should be sufficiently high to ensure that the screws run freely. This is the only way to reduce friction and ensure the longest life possible. Lubrication of screw shafts is an important consideration for any screw.

China Good quality CZPT High Precision Alloy Helical Gear Wheel   near me shop China Good quality CZPT High Precision Alloy Helical Gear Wheel   near me shop

China Good quality High Precision Micro/Mini Worm Gear, DC/AC Brass Worm Gear with high quality

Product Description

Micro worm gear, mini worm gear, dc/ac brass worm gear

We have widely range of design and manufacturing including custom cnc machining, cnc
machined parts, non-standard machine parts, machined casting parts and precision turned
parts that the materials of hardware parts are in steel, stainless steel, brass, aluminum
and plastic. In addition, we specialized in precision parts and components machining to
serve the electronics, automotive parts, astronautical parts, medical appliances and hand
tool industries.

Surface: As your requirement
Material: Steel / aluminum / brass / iron / zinc / alloy
Any other material and dimension depends on customers’ demand.

Usage: Machinery / furniture / toy / woodboard / wall
Manufacturing process: Stamping parts
Euipment: CNC Machining machine
Testing equipment: Projector

Industry Focus Appliance/ Automotive/ Agricultural Electronics/ Industrial/ Marine Mining/ Hydraulics/ Valves Oil and Gas/ Electrical/ Construction
Industry Standards ISO 9001: 2008 PPAP RoHS Compliant

Additional Capabilities CAD Design Services CAM Programming Services Coordinate Measuring Machines (CMM) Reverse Engineering

Specification High Precision Micro/Mini Worm Gear, DC/AC Brass Worm Gear
Material Stainless steel, copper, brass, carbon steel, aluminum
(according to customer’s requirement.
Surface Treatment Zn-plating, Ni-plating, Cr-plating, Tin-plating, copper-plating, the wreath oxygen resin spraying,
the heat disposing, hot-dip galvanizing, black oxide coating, painting, powdering, color zinc-plated,
blue black zinc-plated, rust preventive oil, titanium alloy galvanized, silver plating, plastic, electroplating, anodizing etc.
Main Products Precision screw,bolt, nuts,fastener,knob,pins, bushing, sleeve,gear, stamping parts,washer,gasket,
plastic molding injection parts,
standoff,CNC machining service,accessories etc.
Producing Equipment CNC machine , automatic lathe machine,stamping machine,CNC milling machine,rolling machine,lasering,tag grinding machine etc.
Management System ISO9001 – 2008
Available Certificate RoHS, SGS, Material Certification
Testing Equipment Projecting apparatus, Salt Spray Test, Durometer, and Coating thickness tester , 2D projector
Lead time 10-15 working days as usual,It will based on the detailed order quantity.
Managing Returned Goods With quality problem or deviation from drawings
Delivery of Samples By DHL,Fedex,UPS, TNT,EMS^^
Warranty Replacement at all our cost for rejected products
Main Markets North America, South America, Eastern Europe , West Europe , North Europe, South Europe, Asia
How to order * You send us drawing or sample
* We carry through project assessment
* We give you our design for your confirmation
* We make the sample and send it to you after you confirmed our design
* You confirm the sample then place an order and pay us 30% deposit
* We start producing
* When the goods is done, you pay us the balance after you confirmed pictures or tracking numbers.
* Trade is done, thank you!!
Applications Toy,Automotive, instrument, electrical equipment, household appliances, furniture, mechanical equipment,
daily living equipment, electronic sports equipment, light industry products, sanitation machinery,
market/ hotel equipment supplies, artware etc.

FAQ

Q1:How to guarantee the Quality of Industrial Parts?

A1:we are ISO 9001-2008 certified firm. we have the integrated system for industrial parts quality control. We have IQC (incoming quality control), IPQCS (in process quality control section), FQC (final quality control) and OQC (out-going quality control) to control each process of industrial parts prodution.

Q2:What’s the Advantage of Your Parts for Industry Products?

A2:Our advantage is the competitive prices, fast delivery and high quality. Our employees are responsible-oriented, friendly-oriented,and dilient-oriented. our Industrial parts products are featured by strict tolerance, smooth finish and long-life performance.

Q3:what are our machining equipmengts?

A3:Our machining equipments include CNC milling machines, CNC turning machines, stamping machines,hobbing machines, automatic lathe machines, tapping machines, grinding machines, screw machines, cutting machines and so on.

Q4: What shipping ways our use?

A4:Generally speaking, we will use UPS or DHL to ship the products. Our customers can reach the products within 3 days.If our customers do not need them urgently, we will also use Fedex and TNT.If the products are of heavy weight and large volumn, we will ship them by sea. This way can save our customers a lot of money.

Q5:Who are our main customers?

A5:HP, Samsung, Jabil Group,Lexmark,Flextronic Group.

Q6:What materials can you handle?

A6:Brass,bronze,copper,stainless steel, steel,aluminum,titanium And plastic.

Q7:How Long is the Delivery for Your Industrial Part?

A7:Generally speaking, it will take us 15 working days for machining parts and 25 working days for the for stamping parts products. But we will shorten our lead time according to customers’ demands if we are CZPT to.

Shipping and package

 

Screws and Screw Shafts

A screw is a mechanical device that holds objects together. Screws are usually forged or machined. They are also used in screw jacks and press-fitted vises. Their self-locking properties make them a popular choice in many different industries. Here are some of the benefits of screws and how they work. Also read about their self-locking properties. The following information will help you choose the right screw for your application.

Machined screw shaft

A machined screw shaft can be made of various materials, depending on the application. Screw shafts can be made from stainless steel, brass, bronze, titanium, or iron. Most manufacturers use high-precision CNC machines or lathes to manufacture these products. These products come in many sizes and shapes, and they have varying applications. Different materials are used for different sizes and shapes. Here are some examples of what you can use these screws for:
Screws are widely used in many applications. One of the most common uses is in holding objects together. This type of fastener is used in screw jacks, vises, and screw presses. The thread pitch of a screw can vary. Generally, a smaller pitch results in greater mechanical advantage. Hence, a machined screw shaft should be sized appropriately. This ensures that your product will last for a long time.
A machined screw shaft should be compatible with various threading systems. In general, the ASME system is used for threaded parts. The threaded hole occupies most of the shaft. The thread of the bolt occupy either part of the shaft, or the entire one. There are also alternatives to bolts, including riveting, rolling pins, and pinned shafts. These alternatives are not widely used today, but they are useful for certain niche applications.
If you are using a ball screw, you can choose to anneal the screw shaft. To anneal the screw shaft, use a water-soaked rag as a heat barrier. You can choose from 2 different options, depending on your application. One option is to cover the screw shaft with a dust-proof enclosure. Alternatively, you can install a protective heat barrier over the screw shaft. You can also choose to cover the screw shaft with a dust-proof machine.
If you need a smaller size, you can choose a smaller screw. It may be smaller than a quarter of an inch, but it may still be compatible with another part. The smaller ones, however, will often have a corresponding mating part. These parts are typically denominated by their ANSI numerical size designation, which does not indicate threads-per-inch. There is an industry standard for screw sizes that is a little easier to understand.
screwshaft

Ball screw nut

When choosing a Ball screw nut for a screw shaft, it is important to consider the critical speed of the machine. This value excites the natural frequency of a screw and determines how fast it can be turned. In other words, it varies with the screw diameter and unsupported length. It also depends on the screw shaft’s diameter and end fixity. Depending on the application, the nut can be run at a maximum speed of about 80% of its theoretical critical speed.
The inner return of a ball nut is a cross-over deflector that forces the balls to climb over the crest of the screw. In 1 revolution of the screw, a ball will cross over the nut crest to return to the screw. Similarly, the outer circuit is a circular shape. Both flanges have 1 contact point on the ball shaft, and the nut is connected to the screw shaft by a screw.
The accuracy of ball screws depends on several factors, including the manufacturing precision of the ball grooves, the compactness of the assembly, and the set-up precision of the nut. Depending on the application, the lead accuracy of a ball screw nut may vary significantly. To improve lead accuracy, preloading, and lubrication are important. Ewellix ball screw assembly specialists can help you determine the best option for your application.
A ball screw nut should be preloaded prior to installation in order to achieve the expected service life. The smallest amount of preload required can reduce a ball screw’s calculated life by as much as 90 percent. Using a lubricant of a standard grade is recommended. Some lubricants contain additives. Using grease or oil in place of oil can prolong the life of the screw.
A ball screw nut is a type of threaded nut that is used in a number of different applications. It works similar to a ball bearing in that it contains hardened steel balls that move along a series of inclined races. When choosing a ball screw nut, engineers should consider the following factors: speed, life span, mounting, and lubrication. In addition, there are other considerations, such as the environment in which the screw is used.
screwshaft

Self-locking property of screw shaft

A self-locking screw is 1 that is capable of rotating without the use of a lock washer or bolt. This property is dependent on a number of factors, but 1 of them is the pitch angle of the thread. A screw with a small pitch angle is less likely to self-lock, while a large pitch angle is more likely to spontaneously rotate. The limiting angle of a self-locking thread can be calculated by calculating the torque Mkdw at which the screw is first released.
The pitch angle of the screw’s threads and its coefficient of friction determine the self-locking function of the screw. Other factors that affect its self-locking function include environmental conditions, high or low temperature, and vibration. Self-locking screws are often used in single-line applications and are limited by the size of their pitch. Therefore, the self-locking property of the screw shaft depends on the specific application.
The self-locking feature of a screw is an important factor. If a screw is not in a state of motion, it can be a dangerous or unusable machine. The self-locking property of a screw is critical in many applications, from corkscrews to threaded pipe joints. Screws are also used as power linkages, although their use is rarely necessary for high-power operations. In the archimedes’ screw, for example, the blades of the screw rotate around an axis. A screw conveyor uses a rotating helical chamber to move materials. A micrometer uses a precision-calibrated screw to measure length.
Self-locking screws are commonly used in lead screw technology. Their pitch and coefficient of friction are important factors in determining the self-locking property of screws. This property is advantageous in many applications because it eliminates the need for a costly brake. Its self-locking property means that the screw will be secure without requiring a special kind of force or torque. There are many other factors that contribute to the self-locking property of a screw, but this is the most common factor.
Screws with right-hand threads have threads that angle up to the right. The opposite is true for left-hand screws. While turning a screw counter-clockwise will loosen it, a right-handed person will use a right-handed thumb-up to turn it. Similarly, a left-handed person will use their thumb to turn a screw counter-clockwise. And vice versa.
screwshaft

Materials used to manufacture screw shaft

Many materials are commonly used to manufacture screw shafts. The most common are steel, stainless steel, brass, bronze, and titanium. These materials have advantages and disadvantages that make them good candidates for screw production. Some screw types are also made of copper to fight corrosion and ensure durability over time. Other materials include nylon, Teflon, and aluminum. Brass screws are lightweight and have aesthetic appeal. The choice of material for a screw shaft depends on the use it will be made for.
Shafts are typically produced using 3 steps. Screws are manufactured from large coils, wire, or round bar stock. After these are produced, the blanks are cut to the appropriate length and cold headed. This cold working process pressudes features into the screw head. More complicated screw shapes may require 2 heading processes to achieve the desired shape. The process is very precise and accurate, so it is an ideal choice for screw manufacturing.
The type of material used to manufacture a screw shaft is crucial for the function it will serve. The type of material chosen will depend on where the screw is being used. If the screw is for an indoor project, you can opt for a cheaper, low-tech screw. But if the screw is for an outdoor project, you’ll need to use a specific type of screw. This is because outdoor screws will be exposed to humidity and temperature changes. Some screws may even be coated with a protective coating to protect them from the elements.
Screws can also be self-threading and self-tapping. The self-threading or self-tapping screw creates a complementary helix within the material. Other screws are made with a thread which cuts into the material it fastens. Other types of screws create a helical groove on softer material to provide compression. The most common uses of a screw include holding 2 components together.
There are many types of bolts available. Some are more expensive than others, but they are generally more resistant to corrosion. They can also be made from stainless steel or aluminum. But they require high-strength materials. If you’re wondering what screws are, consider this article. There are tons of options available for screw shaft manufacturing. You’ll be surprised how versatile they can be! The choice is yours, and you can be confident that you’ll find the screw shaft that will best fit your application.

China Good quality High Precision Micro/Mini Worm Gear, DC/AC Brass Worm Gear   with high qualityChina Good quality High Precision Micro/Mini Worm Gear, DC/AC Brass Worm Gear   with high quality