[Shalecnc]

I'm pricing ballscrews for my build and really like the Misumi product line; it's easy to customize, generates 3D cad models etc. Misumi offers C7 and C10 grade ballscrews -- for 1000mm assembly, that's $200 for the C10, $327 for the C7.

Unfortunately the Misumi C7 is a bit more than the Chinese-made "C7" grade avail on ebay and other dealers; whereas the Misumi C10 is price comparable.

But... Are the Chinese ballscrews actually C7 grade, or is their C7 grade more comparable to Misumi's C10 grade? Has anyone ever tested/measured the Chinese screws to confirm they meet C7 grade specs?

I'm tempted to go with the Misumi C10 grade and figure that's about as good as a mystery Chinese made ballscrew. Would that be a big mistake?

[Shalecnc]

Theoretically, a C7 grade ballscrew has 50 μm variation/300mm travel; C10 grade is 4 times that at 210μm variation/300mm.

Over a 1000mm ballscrew travel, that's almost .0275" variation. Can Mach3 be callibrated for that variation?

[JerryBurks]

Don't know about the Chinese screws.

But it makes me really appreciate that I got my GG1515 C5 grade Kuroda screws for $130 each.

Now there are GG2020 Kurodas on ebay KURODA 43" BALL SCREW (3/4" SHAFT) GG SERIES 20-20 A WITH CLUTCH | eBay

[RicknBeachcrest]

Fwiw,
I got a pair of the misumi ball screws. In my opinion, well worth the money.

Rick

[louieatienza]

Don't know about the Chinese screws.

But it makes me really appreciate that I got my GG1515 C5 grade Kuroda screws for $130 each.

Now there are GG2020 Kurodas on ebay KURODA 43" BALL SCREW (3/4" SHAFT) GG SERIES 20-20 A WITH CLUTCH | eBay

The guy I bought three of the same ones from has some on for about $80 each (I first bought three of them at $65) so I had to buy three more to hoard.

As to the "chinese" screws it seems to be hit-or-miss. There are many here who had success with them, and there are a few that had problems. One guy in the MetalWorking section that gets .002" backlash, though I don't know if this in addition to any lead error. Misumi sells good stuff so if they tell you it's C10 or C7 you could be sure it's at least that. It also may be a moot point depending on your needs and materials being cut.