Importing a "Genuine" Timken tapered bearing from China! Is it illegal and are any firms t

[AsherDK]

thread821-250073

Happy holidays everyone! This is my first post and I am hoping that Your experience might allow me to buy tapered bearing sets without having to pay the highest rates unnecessarily!

I need a pair of HM535349/HM535310 tapered bearings to support a steel boat sculpture that aligns itself with the wind to decrease the wind load. The weight of the sail and masts come to about 3.000lb

I was shocked at the prices of the bearings up to $6,000 for the pair. Hunting I found one USA source for $3,700. From China one can fine prices for $700 to $1,500 a pair for "Genuine" Timken. but the question then arises as to whether they will get though customs as it appears that the blockade of bearings import has only been dropped for everything but tapered bearings from China.

Then there are copies. These go from $220 for two sets up to $800 a pair. however, so far the few companies I have asked, do not provide U.S. customer references on the grounds of privacy! There are no reviews I have found. I have no time to do testing apart from just examining the looks of it and giving the parts to my fabricator who is building the housing.

I do know that Timken manufactures in China but then the steel is especially sourced and quality controlled. The machining is done under Timken supervision. There are, however many hundred of small and large machining shops in China with ranging from very old fashioned tooling with whatever steel is available and the modern factories who perhaps also manufacture bearings for the great name brands. However, I have seen no authoritive guide to this maze of varied quality!

The bearing assembly is going to be welded into the spine of the "boat" hull of the sculpture so it would add about $2,000 at least, just to change a bearing that failed plus the cost of the replacement!

Are there high quality equivalents made in Germany, Sweden or Japan that folk stock in the USA. I would appreciate if anyone has a connection that has proved reliable so I can shop outside of the "look" of the packaging, (copies are can be packaged far better than originals), and outside of just picking a top price of the copies or assuming that the "genuine" Timkens are in fact just that? Lastly can one even import such bearings from China these days?

Thanks in advance!

Asher

 

[MikeHalloran]

Jib cranes are commonly made with ONE tapered roller bearing at the top to carry all the dead weight and the load, and a pair of sturdy roller bearing rollers (like the "wheels" you see under garbage gondolas) riding several feet down on the mast to carry the moment.

So you may not need _two_ tapered roller bearings, if you can substitute an array of rollers located some distance down along the rotation axis, for the lower tapered roller bearing.

Note also that even if you use two tapered roller bearings, they don't have to be the exact same size; the lower one can generally be smaller, like the outer bearing on a car's front spindle was when they didn't use unitized bearings.

The size difference can be larger as the bearings are moved apart axially; you probably could benefit from some local engineering help.


Separately, I have bought ball bearings made in the Czech Republic from my then local supplier, and so far as I know, they worked okay. Bearings are an international business these days, so if a local retailer is ready to stand behind what he sells, and I've engineered an installation in accordance with accepted standards and practices, I can find other things to worry about.



Mike Halloran
Pembroke Pines, FL, USA

 

[AsherDK]

Mike,

Thanks very much! What are you approaches to estimating by how much one can decrease the diameter of the lower bearing? Is it just taking the oblique moment?

Asher

 

[MikeHalloran]

Sure.
An FBD should resolve the statue's weight into a vertical force along the axis, which you can react through the upper bearing, and a moment that decomposes into two equal horizontal/radial forces, plus the moment from the wind.
Put the FBD in a spreadsheet and play with the bearing spacing and the bearing ratings.

Try to restrict your selection to bearings that you can buy locally, so you don't have to worry about customs related matters.

It might be a good idea to visit your local bearing suppliers in person, to try and figure out which employee at each place is equipped and authorized to deal with unique requests.





Mike Halloran
Pembroke Pines, FL, USA

 

[geesamand]

"Inch" nominal sized taper roller bearings are one of the last bastions of Timken's wealth that are still protected on some level by anti-dumping regulations. But those walls are well on their way to coming down. Contact NSK, NTN, Koyo, for example to see if they have that cup/cone combination on hand. Their bearings are very close or equal to the Timkens and the tolerances and fits are essentially the same. In fact in your application where speed is nearly zero, you might compare the static load ratings (and find them to be equal across brands).

Unfortunately Timken has a massive catalog of these taper roller sizes and the competitors are just getting started trying to fulfill the requests. You could well find that only Timken makes the bearing you want.

 

[Compositepro]

I cannot imagine why such an expensive bearing would be considered for such an application. Wheel bearings for trucks can handle the stated load and they cost a small fraction of what has been described here.