Boatload of Hiwin 64" ballscrews on ebay

[NC_jimbo]

Looks like somebody bought a boatload of ballscrews from China
and selling them on Ebay one or 3 at a time.

Has anybody done the homework on these? I see patial info on hiwin site but catalog just seems to have picture of RSV model but not the specs. Am I missing it somehow? If so a PDF link and page # would be nice.

I'm like to stay in the 1 mil tolerance range on a 48"x30".

I can't even figure out if its a "precision" or "High precision" screw.
I blew up the drawing included on ebay and see that
backlash=0.2mils

Any opinions??

[SORCHEROR]

i emailed the guy and they are precision rolled ball screws,with single preloaded nut,thats all i know

[NC_jimbo]

Bidders are being silly at this point. Bidding a single unit up to $275 while someone bought a pkg of 3 for $375. He's got a huge pile of em stacked up, relax and wait until the desperate/unknowing are out of the way.

He references an economy fixed side support unit. Do you know what you'd do for that end? Is it back to ebay for that or is there a stocked item you know of?

[lgalla]

From McMaster carr a similar screw is about $120 and $172 for the nut.About 300bucks,if 64"is your required size the Hiwins are a good deal.The angular bearing blocks he sujested are a bargain.ThK's are $300 or more.
Larry

[NC_jimbo]

So here is the spec for the BRW support unit that he references.

I agree that the $70 price looks good compared to a $200+ THK but there isn't a single performance spec that I can see compared to THKs spec on page 4.

Somehow I doubt that all support blocks are the same?

[phantomcow2]

I have the same exact screws on my X3 (except cut way down!). Mine were about 36" though, with journaled ends. Except mine have inspection reports to accompany. According to this, they have a 4.7 micron deviation over the 300mm threaded portion. The nuts are completely backlash free

[NC_jimbo]

That sounds good.
Can I ask what bearing solution you used for the supported end?

[NC_jimbo]

In the right lower corner corner of Misumi BRW spec tells us that they use a GMP5 class angular bearing whose axial load N rating is within 10% of THK. So as long as you think a GMP5 of Misumi is approx as good as a Misumi class5 then the Misumi seems like a fair deal at <1/3 the cost.

[phantomcow2]

Since these screws are hardened all the way through, I decided not to even bother to turn down the end of the ballscrew. I used a surface grinder with an abrasive cutoff wheel to cut it off, which it did very smoothly. And I used a 20mm ID bearing and it fit on, and made my bearing block support that. The ballscrew is the tinniest bit over 20mm, so I had to lightly sand with 600grit paper for 2 or 3 minutes and it was a good fit.

[NC_jimbo]

I'm really showing my chip sweeper status.....
I meant to ask about your FIXED end bearing set.

Although you told a good story for the supported end.

[phantomcow2]

Oh, I bought a set of 10mm angular contact bearings, and preloaded them myself with bearing blocks I made.

[Armstrong]

Really?I think I have to check eBay or contact that guy for his products.

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