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

[rhb]

NSK 7205 P4 bearings are $400-500 each from an NSK distributor and about $150-200 more from Grainger. Much to my astonishment, there isn't an NSK distributor in Little Rock, but there are some closer. Times have changed.

"7005CTYNDBLP4" is not a bearing listed by NSK either online or in the online catalog. And the "7005CTYN" is a 25 x 47 x 12 mm ABEC 1 bearing. The "7005CTYNDBLP4" is only available on ebay. Pretty trivial to take a genuine ABEC 1 bearing and add some letters to the label. The number of listings for those is quite surprising. I think NSK needs to have a word with ebay about counterfeiting.

$1000 for new bearings is a bit too much of an upcharge. I do not need high spindle speeds, so plain bearings will do and I can make those. That's also the only option if you require zero rotational errors. I'll look for suitable P4 rolling bearings later. I've had enough of completely screwball websites for this morning. One let you select ID & OD, but not width or class. I was not willing to page through 639 items looking for things that *might* be appropriate.

I'm expecting a long phone call with Boca Bearings tomorrow :-(

BTW Does anyone think these are real?

NEW NSK 7205CTYNDBLP4 Abec-7 Super Precision Spindle Bearings.Matched Set of Two | eBay

Find many great new & used options and get the best deals for NEW NSK 7205CTYNDBLP4 Abec-7 Super Precision Spindle Bearings.Matched Set of Two at the best online prices at eBay! Free shipping for many products!

www.ebay.com

 

[rhb]

FWIW Here's an example of why I'm screwing around with this job:

https://www.digikey.com/en/products/detail/rosenberger/60S101-K066/8592660

This is a bog standard M-F adapter used to protect a connector on an instrument. Take a look at the datasheet. Then imagine what Rosenberger would want for a custom part.

You do not want to teardown a million dollar instrument to replace a panel connector. So you put these on and when they wear out you replace them. I have the electronic lab gear to validate electrical performance to 40 GHz. That eliminates 99+% of job shops from consideration. Physical inspection is "necessary, but not sufficient". Please note the 5 um tolerance on the 6.975 mm inner conductor.

I'm definitely *not* going to mess with something like this. It's out of my league, but I doubt that many here are aware of high frequency RF connectors cost and tolerances so I thought it might be useful to point out. At least to some.

 

[APD]

NSK 7205 P4 bearings are $400-500 each from an NSK distributor and about $150-200 more from Grainger. Much to my astonishment, there isn't an NSK distributor in Little Rock, but there are some closer. Times have changed.

"7005CTYNDBLP4" is not a bearing listed by NSK either online or in the online catalog. And the "7005CTYN" is a 25 x 47 x 12 mm ABEC 1 bearing. The "7005CTYNDBLP4" is only available on ebay. Pretty trivial to take a genuine ABEC 1 bearing and add some letters to the label. The number of listings for those is quite surprising. I think NSK needs to have a word with ebay about counterfeiting.


BTW Does anyone think these are real?

NEW NSK 7205CTYNDBLP4 Abec-7 Super Precision Spindle Bearings.Matched Set of Two | eBay

Find many great new & used options and get the best deals for NEW NSK 7205CTYNDBLP4 Abec-7 Super Precision Spindle Bearings.Matched Set of Two at the best online prices at eBay! Free shipping for many products!

www.ebay.com

I think you know the answer to this.
1/4 the price
Unknown seller from China on Ebay
Numbers dont match with NSK

High probability of counterfeit

 

[rhb]

Precisely why I would *never* ever consider buying precision bearings on ebay.

I do a lot of electronics stuff and have a suite of lab gear (much bought on ebay) that when new in the mid 90's cost $500K. All HP, Tektronix or one of the very few other top tier vendors.

Unlike metalworking kit, it's readily available for 1-2 cents on the dollar. And still works as well as when new. The new stuff is better, but it doesn't make the old stuff any worse. And there isn't anything I know of to match a Tek 11801A with an SD-24 sampling head which has 20 GHz BW and will show an electrical defect which is 0.01 mm long.

Unfortunately, that's not true of the connectors, adapters, cables etc. Those wear out, so used stuff is often junk. So one has to be very careful from whom one buys it.

I have a long running thread on the eevblog.com forum demonstrating testing of various RF cables, connectors, etc. Seeing a reflection which takes place over 0.01 mm along a coaxial cable is pretty amazing. And unlike physical metrology, it's much easier to validate the results.

 

[jim rozen]

OK you're a stud, but none of this has any relation to the lathe bearings you think you need to replace. Focus.

 

[johansen]

Google search just the tyndblp4 suffix and you will probably conclude those are not nsk bearings.

 

[Robert R]

Hello :
Fun facts from the NSK catalog on page 256:

NSK - Motion & Control

www.nsk-literature.com

7005CTYNDBLP4
7005 = ANGULAR CONTACT BEARING WITH A 25 MM BORE
C= 15 DEG CONTACT ANGLE
TYN=POLYAMID CAGE
DB= MOUNT BACK TO BACK
L=LIGHT PRELOAD
P4= ACCURACY CLASS
The good thing about counterfeit bearings is that they also depress the price of the genuine new old stock bearings. At best one ends up with a genuine NSK bearing at a low price. At worst one may end up with a good copy.

 

[memphisjed]

OK you're a stud, but none of this has any relation to the lathe bearings you think you need to replace. Focus.

Is this all for the mini lathe to CERN lathe conversion?

 

[mottrhed]

Couple things, first yes there have been NSK bearings counterfeited, so buying from a reputable source is key--regardless of mfg you choose.

Second, what is the application? What exactly (oem+part number) was removed? When you talk about going from angular contact to plain bearings.. I get the sense you arent understanding the difference between the two. And if you can "make" plain bearings for less than the $1000 you are worried about, Ive got some work to send your way.

I think you are overthinking this, cross the part removed to a known quality part from a vetted vendor (they will do it for you if you ask), reassemble and get back to making parts.