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?