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Anyone have experience with ABEC 7 bearings from Xin Ha Accurate Bearings?

rhb

Aluminum
Joined
Apr 27, 2019
Location
A small town in central Arkansas
I bought a pair of 7205C-P4-DGA bearings from Boca Bearings which touts itself as a maker of high spec bearings. I was a bit disconcerted when I received them only to find they were Chinese. I was expecting them to be a Boca Bearings product. However, Apple, Keysight, Tektronix, Amphenol and a myriad of other high end suppliers have outsourced production to China and it is not uncommon to find counterfeit crap. The problem is so bad that who you buy stuff from matters as much or more as who made them.

Does anyone have any experience with Boca or Xin Ha? I'm particularly concerned about Chinese "4th shift" products, out of spec rejects that get substituted for good parts by an unscrupulous employee in the shipping department. Counterfeiting SKF bearings is an organized crime operation. A bit of sleight of hand by an employee is much harder to police. I already have first hand experience with this in the electronic component field.
 
If you can't measure the difference yourself, how can you tell the actual quality of the bearing regardless of where it is manufactured?
 
^^^what technocrat said^^^
The only way you have to verify the quality is to put them into service (unless they are so bad that they are obviously defective, and then you just return them without using)
So either use them or buy bearings with a name printed on them that makes you feel good, from a vendor with a name that makes you feel good.
You will still have to put them into service to determine if they are good or not.
If it is something so critical that you are not willing to take the risk of an inferior product, then spend the extra money to get the brand/name/country that makes you feel good.
Good and bad products come from all countries. When in doubt, dont buy the cheapest.
 
My experience with Chinese bearings is with tapered roller style. The rollers are case hardened mild steel rather than through hardened. Failure mode is entirely different than a Timken and they do not last. But they look great!

Ed.
 
My experience with Chinese bearings is with tapered roller style. The rollers are case hardened mild steel rather than through hardened. Failure mode is entirely different than a Timken and they do not last. But they look great!

Ed.
Hiwins are pretty darn good.
 
You will still have to put them into service to determine if they are good or not.
How do I know heroin is bad for me?
I mean, each of us would have to try it for ourselves to fin out, right?

OP is here asking for the product's reputation, because products from China ARE SUSPECT

The difference between a wise man and a smart man is that the smart man learns from his own mistakes, the wise man; other's.
 
I wouldn't know anything about scientific instruments.

https://www.esmats.eu/amspapers/pastpapers/pdfs/2012/miller.pdf

Nice work - in the publication it looks like you were measuring a single radial bearing in each case. Yes?

Lathe spindles typically use angular contact pairs, sometimes a pair run with OD and ID spacers (aka hardinge HLVH style) and sometimes a back-to-back pair at the front and a single radial at the back end. What's the setup in your lathe?

Ah, close reading shows db pairs. How were the inners and outers clamped up?

Also, the asynch errors are all about the same. Could part of that been noise in the measurement devices and signal processing? The discussion of the fixture evolution was of considerable interest.
 
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How do I know heroin is bad for me?
I mean, each of us would have to try it for ourselves to fin out, right?

OP is here asking for the product's reputation, because products from China ARE SUSPECT

The difference between a wise man and a smart man is that the smart man learns from his own mistakes, the wise man; other's.
In this example, the OP needs good heroin, he's not deciding whether or not to try heroin at all.
He wants to know if the heroin in front of him is good heroin or bad heroin, and whether or not he should try it.
He suspects the heroin may be bad, and that even high quality heroin is often counterfeit.
No one can know what he has.

So I suggested he buy heroin that he is comfortable with in regards to name/country/vendor/cost, and assess the risk based on his situation. Because that is what ultimately matters. He already has the heroin. The experience of others may influence his decision whether to return them or not. If he does, then he will again have to make the same decision about brand/country/vendor/cost and still be suspicious of counterfeits. And in the end he will only know if he made the "right" decision by putting them into service and seeing if they last.
 
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Hiwins are pretty darn good.

I talked to the Hiwin rep at the MD&M show in Anaheim a few years ago. He said the only way to guarantee that you were getting genuine Hiwin products was to order from Hiwin direct.

Any other source could be suspect.

Of course he's bound to say buy direct from Hiwin, on the orther hand the Chinese making fake Hiwins products wouldn't be a surprise. Seemed very plausible
 
Hiwin has factories in China... fakes can be made anywhere.
Why order from them, when I can go to a bearing supply house 10 minutes down the road and have them in my hand same day?
 
Hello RHB: I am puzzled why you would pay $60.00 each for off brand unmatched class P4 angular contact bearings when you could have bought for $100 a matched pair of NSK 7005CTYNDBLP4 Abec-7 Super Precision Spindle Bearings while you were searching on Ebay.


The majority of the discussion on this thread and the related one in the Metrology forum has concerned questions about bearing quality. If your interest is in obtaining fully tested bearings from a known supplier would it not make more sense to purchase the matched NSK bearings and save a few dollars in the process?

A second point: The PDF article you referenced concerning bearing testing is of no value. Spindle bearing sets are not used in the manner shown in the fixture. Bearing sets on spindles are spaced roughly 2.5 X the spindle diameter apart to maximize the radial stiffness at the nose of the spindle. The high spots on the forward and rear bearing matched sets are aligned to minimize angular offset at the spindle nose. The angular deviation of either the forward or rear bearing pair is not relevant. Angular deviation of the spindle nose is determined by the center line displacement of each bearing pair during rotation rather than the bearing pair "wobble" described in the paper.

The stated goal of the Lockheed paper is to examine the use of ABEC class 3 bearings in the satellite business for the cost saving. This is meant to be a joke.
 
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Robert R:

I would not buy precision bearings from ebay. That's asking for trouble. There are thousands of Chinese merchants with fulfillment warehouses in the US. Great way to peddle counterfeit or reject stuff. Shipping to US is subsidized by both the US and China. Returns are not. So it's easy to get burned.

Here's the home page for Boca Bearings and product page for what I bought. I didn't see anything dodgy looking about the website and it has a functional search facility unlike far too many sites which do not. I actually came upon Boca by way of a bearing cross-reference site. So I was quite disconcerted when I opened the package. I plan to discuss returning them with Boca on Monday. The lack of a mention of the maker led me to expect they were made by Boca.

Yeah, the paper isn't very good. It was part of a NASA Webb Telescope conference proceeding. I simply grabbed something as an example of bearing testing that wasn't lifetime focused. I just skimmed over the paper before I posted the link.
 

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That right there is all a person needs to see to know they're not getting the real thing. Genuine Super Precision Angular Contact Bearing sets can not be bought for anything less then roughly 3-7 times that.

I suggest a person find a local supplier with history and a good reputation, and are a certified supplier for whatever name brand you like to use. Many around here use a decades old local bearing/drive supplier. (Tull Bearing) They don't even have a website on the www as they don't need it to stay busy. People just know.
 
In my case, a "local" supplier of anything other than automotive bearings is 75 miles (Little Rock) or 150 miles (Memphis). This is not exactly a hub of industry. Grainger is the only option in Little Rock. I use them when I *have* to have it running ASAP and they have it in stock. If not, they are the slowest option. And invariably the most expensive. When I was in Dallas or Houston it was just a trip across town to get pretty much anything and I knew who to call to check availability.
 
Hiwin has factories in China... fakes can be made anywhere.
Why order from them, when I can go to a bearing supply house 10 minutes down the road and have them in my hand same day?
well you got that going for you . so you the 10 min. baring man
 








 
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