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UIPI slewing bearings


UIPI Slewing Bearings, we produces consistent quality, custom slewing bearings that reduce your cost and save your time through precise engineering, and 100% traceable, complete in-house manufacturing. It is our goal to be strategically aligned with business partners more than just suppliers.

A Story about “Rejecting” a Client

One day, I received an inquiry from a Colombian customer,  with no drawing, only the P/N.


But this is a slewing bearing only we can produce, with no competition.

Because it’s a private label slewing bearing for one of our OEM customers in the US.


He required two pieces(we keep inventory for regular OEM customers), and asked to send them by air.

He also wanted to sign a contract with us, to be the exclusive agency of this customer in the aftermarket of Colombia.

Sounds nice, right?

But we told him to contact the OEM customer directly, please.


We’ve promised the OEM customer “We will NEVER sell your slewing bearings in the aftermarket”

We understand protecting the aftermarket value of our OEMs.


We believe in the basic business rule - Saying what we’re going to do, and doing what we've said.

Regardless if you're buying one slewing bearing or one hundred,

each purchase order we fulfill comes with a detailed inspection report, including

dimensional testing, hardness testing, chemical composition and metallurgy,

all the certificates, tests, and product pictures you will get prior to each shipment.

Industries Served

Here are some typical industrial applications for which we have supplied slewing bearings.

How are We Different from Others?

Slewing Bearing Manufacturing Process

Get a Glance at How Your Slewing Bearings are Manufactured

Our slewing bearings are produced with modern CNC machines. All the processes done in-house, including heat treatment, which is a very important process for consistent quality.

Optimal Design - Provide the Best Possible Solution for Your Project

With your input, our in-house engineering experts with rich hands-on experience are capable to provide the best possible slewing bearing for your project. 

Slewing Bearing Design Drawing
Slewing Bearing Inspection

Consistent Quality - the Solid Foundation of Your Business

We utilize a series of specific and strict inspection measures throughout the manufacturing process to ensure consistently high quality. Each slewing ring is stamped with  a unique tracking number for complete tracebility, per ISO and API specification. 

A Safety Net - We Issue $2M Liability Insurance for Customers!

Many potential customers think working with Chinese manufacturers comes with certain risks. Understanding these concerns and stigma, we issue $2 Million in liability insurance for each of customers as a safety net.

Certificate of Liability Insurance

Do you have any processes that need to be outsourced?

Of course, yes. We’re a manufacturer, but that doesn’t mean we don’t need help. We need to outsource grinding if the bearings have special requirements like pre-loading. We need to outsource this procedure if the bearings need painting or coating. 

CASE STUDY: How we Helped an Customer Reduce Cost by 30%
They were eager to update their aged product lines based on customer input. But they had not seen any issues with their previous slewing bearing suppliers, nor had their customers suggested any slewing ring problems on their equipment...

Frequently Asked Questions & Answers

UIPI has been manufacturing slewing ring bearings for 10 years and we have encountered all kinds of problems, here are the most important concerns of our customers.

I need a slewing bearing for my new project but don't know what bearing will fit. Can you help? 

Of course. In fact, we consider engineering and design to be our core advantages. Our engineering team has designed hundreds, if not thousands, of customized slewing bearings for customers' specific projects. We're competent in providing the most suitable slewing bearing to your application. We'll work with you through every step of the design phase, and we understand that in the prototype stage, the quantity will not be large; we're happy to accept small quantity orders. 

The old slewing bearing on my crane or excavator need to be replaced. Can you provide a new slewing bearing?

Yes, as long as you can provide us with the drawing of the slewing bearing you require, were able to help. While we can occassionally help via brand name and model number, such as Hitachi, Komatsu, Kobelco, etc., OEMs work hard to protect their drawings so our ability to help is limited. If sending us the bearing is an option, we can reverse engineer it and send a new replacement as well.

I don't have a slewing bearing drawing for my excavator or crane. Still, I can provide all essential dimensional data, including inner and outer diameter, height, mounting bolt size and quantity, gear teeth quantity, etc. Can you provide a replacement quote for my slewing bearing?

As mentioned before, we have designed thousands of different slewing bearings. While many of those bearings are vastly different in size, gear configuration, etc., some are only differentiated by bolt thread size, grease fitting type, or other small revisions. In order to provide a quote for a true replacement bearing, we would ideally need a drawing.

What slewing bearing gear tooth data do you need? What if I can measure it by myself?

Theoretically, it's available, but as we just spoke about, slewing bearing gear teeth are complicated! While we can get an idea of tooth form and size through calculations, we wouldn't be able to match perfectly if there are modifications (stub, full depth, addendum or dedendum mod coefficients, etc.). In the best case scenario, we get it close or spot on, and everything works well. Worst case, the tooth form is slightly off, leading to improper meshing and substantially shorter bearing life and damage.

I need an equivalent slewing from another slewing bearing manufacturer. Can you help?

Yes, we can cross-reference all manufacturers' slewing bearings. Please provide us with the drawing, or let us know the slewing bearing brand name and the model number, like Kaydon MTO-415T, so that we can search for more detailed information to confirm and quote you the price. 

What should I do if I want to get the price of a slewing bearing?

A. If it’s for a replacement and you have the drawing, please provide us with the drawing so we can quote. 
B. If it’s for a new project, we need to design it first, then quote. Please provide detailed information on slewing bearing requirements, such as the general dimensions, requested loads and moments, rotation speed, working conditions, and gear preference. The more details, the better. If you have sketches, pictures, or videos, please share with us, as they will help with design. 

I’m an engineer working on a new application. Can you provide drawings?

Yes. All bearings come with a 2D PDF drawing with every detail you need, including a static load capacity curve for your reference. To help visualize the end product, and pinpoint any necessary changes, all of our standard drawings are to scale. Further more, we can also provide 3D solid model for your assembly and installation to simulate working condition. 

Are you a slewing bearing manufacturer or a trader? 

We are a slewing bearing manufacturer, with all production process done in-house. Further, we do not supply our bearings to any traders in China. Instead, we prefer to work direct with end users to provide the best customer service possible. 

Manufacturing in-house? Don't all manufacturers do that?

Surprisingly, no! Many slewing bearing manufacturers in China oursource the heat treatment process, as it is difficult, expensive, and imperitive to proper bearing life and function. However, we saw inconsistencies in the quality of these facilities, so we purchased high-end machinery to do all heat treatment of raceways and gear teeth in-house. We require attention to detail and quality control at EVERY step of manufacturing.

How many slewing rings do you produce annually?

Our production and sales capability keep growing thanks to our consistent quality and customer-oriented service. We have delivered at least 30,000 of slewing bearings over the past five years. Last year(2021), we delivered almost 8,000 of bearings. 

Slewing Bearing

Do you have any processes that need to be outsourced?

When a bearing requires a specialized, out-of-the-norm treatment, we partner with a close by manufacturer to handle these processes, while also sending one of our workers to observe. For example, if a bearing requires painting or specialized coatings, we work with a manufacturer that excels in that field. Likewise, if a bearing raceway or gear teeth require very high precision grinding, we will work hand-in-hand with them to complete the work to our requested tolerances.

My project needs bearings with internal/external gear teeth. Can you offer the mating pinions? 

Yes, we're a one-stop shop to fulfill all your rotational requirements! Once the bearing design is completed, we can design a pinion with full confidence they will mate properly, leading to prolonged life. We can modify the pinions to account for your input, be it a key, spline, etc.

We are an OEM manufacturer and can forecast our production requirements. Will you keep stock for us?

Absolutely! As we build our relationship, we are happy to keep an inventory of your bearings for scheduled releases. Through inventory management at our California warehouse, we can ensure you receive your bearings on time, every time.

What are typical lead times for slewing ring bearing? 

Generally speaking, our production lead time is 6-10 weeks, depending on the slewing bearing complexity. Different processes, such as grinding, gear teeth heat treatment, or coatings take more time to complete. From there, transportation takes between 10-40 days, depending on options. Overall, our standard lead time is 12-14 weeks.

Do you have any certificates?

Yes, UIPI strives to continuously improve all aspects of its business, including manufacturing, engineering, and customer service. In addition to ISO Certification, After two years of rigorous examination, along with random yearly audits, we have completed the process of becoming registered with the American Petroleum Institute (API). 

Do UIPI Bearings come with a warranty?

Yes. A one-year warranty is offered on all UIPI slewing bearings. We also understand some customers hesitant to work with Chinese manufacturers. In addition, we issue liability insurance for each of our customers, covering up to $2,000,000.00. We have never had to use this coverage, but it acts as a great safety net for those hesitant to work with Chinese slewing bearing manufacturer.

The Ultimate Guide to Purchasing Slewing Bearing in China

Improve Your Purchasing Experience Today

Whether you're trying to reduce cost, improve quality, shorten lead time, or find an application engineer, we appreciate any opportunity to help. 

The Ultimate Guide to Purchasing Slewing Bearing in China
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